ExhaustionConsumer rightsPatent marking

Patented products: what it means to buy one

By Ipiry TeamPublished September 1, 202610 min read

Short answer

Buying a patented product from an authorised source exhausts the patent holder's rights in that item, so you may use it, resell it and repair it freely. What you may not do is make another one. A patent usually covers one feature rather than the whole product, and the marking tells you a patent exists rather than what it covers — the claims do that, and they are public.

Patented products raise a different set of questions from patents themselves.

The owner's question is what they can stop others doing. The purchaser's question is what they may do with the thing they bought.

The answers are more generous than people assume. Buying from an authorised source exhausts the patent holder's rights in that item, so using, reselling and repairing it are all permitted.

What you may not do is make another one. Exhaustion attaches to the item, not to the technology.

What the marking actually tells you

Marking	Means
"Pat. 10,456,789"	A granted patent, identified
"Patents: example.com/patents"	Virtual marking — check the page
"Patent pending"	An application on file; nothing enforceable
"Patented" with no number	Unverifiable
Several numbers	Several patents, each probably narrow
Nothing at all	Does not mean unpatented

Marking is optional. Failing to mark limits the owner's damages for the period before actual notice, which is a penalty on them rather than a signal to you.

A number is checkable in minutes. Look it up in Google Patents or USPTO Patent Public Search and read the independent claims. See patent number.

What the numbers on a product tell you

Observation	Inference
One number	One feature protected
Several numbers	Several features, each narrow
A D-prefixed number	Appearance protected
"Patent pending"	An application, nothing enforceable
A virtual marking URL	Check the page — it may be current
An old product, old numbers	Likely expired — check
No marking	Says nothing either way

More numbers does not mean broader protection. It usually means several narrow claims covering several features, each of which can be avoided independently.

Virtual marking pages are more reliable than moulded numbers, because they can be corrected when patents lapse. See patent marking.

A patent usually covers one feature

Assumption	Reality
The whole product is protected	Usually one mechanism or composition
Four numbers means four patents on the product	Four narrow claims on four features
Nobody can make anything similar	Competitors work outside the claims
The title describes the coverage	The title has no legal effect

A product titled as a filtration system may be covered by a patent claiming only a valve seat geometry. Everything else about it is unprotected.

Which is why reading the claims matters if the question is whether you can build something similar rather than whether you can use what you bought.

Exhaustion: what buying gives you

An authorised first sale exhausts the patent holder's rights in that item.

You may	You may not
Use it	Make another one
Resell it	Reconstruct a spent article
Repair it	—
Modify it for your own use	Manufacture the patented feature separately
Import it, if bought abroad from an authorised seller	Import from an unauthorised maker
Lend or give it away	—

Exhaustion follows the article. Buying one authorised unit gives no right to produce more, however thoroughly you understand it.

The source matters. If the seller was not authorised by the patent holder, exhaustion does not apply and using the item can infringe.

International exhaustion

Purchase	US rights exhausted?
From the patent holder in the US	Yes
From an authorised licensee in the US	Yes
From the patent holder abroad	Yes — Impression Products v. Lexmark
From an authorised foreign licensee	Yes
From an unauthorised maker anywhere	No

Impression Products settled this in 2017. An authorised sale anywhere in the world exhausts the holder's US patent rights in that item, so parallel importing an authorised product is permitted as a patent matter.

Customs and trademark issues are separate. Exhaustion answers the patent question and not necessarily the others.

Single-use and post-sale restrictions

Restriction	Enforceable as a patent matter?
"Single use only"	No, after an authorised sale
"Not for resale"	No
"Return after use"	No
Contractual undertaking you signed	Possibly, as contract

Impression Products also settled this. A patent holder cannot use patent law to enforce post-sale restrictions once they have sold the item, even where the restriction was clearly stated.

Contract is a different route. A term you actually agreed to may bind you personally, but it does not travel with the item to a subsequent buyer.

Repair versus reconstruction

Activity	Generally
Replacing a worn consumable	Permitted repair
Replacing a broken component	Permitted repair
Replacing several components over time	Usually repair
Refurbishing for resale	Frequently repair
Rebuilding from a spent article	Reconstruction — infringes
Making a new article using one old part	Reconstruction

The test is whether the article as a whole was spent and whether what was done amounts to making a new one.

Repair is a real right, not a tolerance. It follows from exhaustion, and it is what makes an aftermarket parts industry possible.

Aftermarket suppliers are more exposed than repairers. A part designed to fit only one patented assembly may fail the staple article defence. See contributory patent infringement.

Design patents on products

	Utility patent on a product	Design patent
Prefix	None	D
Covers	How it works	How it looks
Term	20 years from filing	15 years from grant
Maintenance fees	Three	None
Almost always in force?	No — 58.6% lapse	Yes
Stops	Functionally equivalent products	Products that look the same

A D-prefixed number is far more likely to be live than a plain number of similar age, because no fees are due and nothing can be missed.

It also restricts something different. A design patent stops a lookalike, not a functional equivalent that looks different — which is the opposite of what most purchasers assume. See types of patents.

Checking whether the patent is still live

Step	Where	Time
Read the number	The product	1 min
Confirm the patent exists	Google Patents	2 min
Read the independent claims	Full text	15 min
Check maintenance fee status	USPTO Patent Center	3 min
Check current ownership	USPTO Assignment Search	5 min

Ipiry Patent Survival Curve v1.0	Rate
Survive the 3.5-year fee (2022 cohort)	85.8%
Survive the 7.5-year fee (2018 cohort)	64.6%
Reach full term (2014 cohort)	41.4%
Abandoned before full term	58.6%

Computed from 27,273,654 USPTO maintenance fee records covering 8,262,336 US utility patents — see the patent survival curve.

Markings outlive patents routinely. Nearly three in five utility patents lapse before term, while moulded numbers stay on products for years afterwards.

Marking with an expired patent is expressly excused from false marking liability where the patent once covered the article, so a stale number is usually an oversight rather than a deception.

Worked example: a marked appliance

A kitchen appliance marked with three patent numbers.

Number	Type	Claims cover	Status
9,xxx,xxx	Utility	A specific blade geometry	Expired 2023
10,xxx,xxx	Utility	The locking mechanism	In force
D8xx,xxx	Design	Ornamental appearance	In force

What that means for a purchaser

Question	Answer
Can I use it?	Yes — exhausted
Can I resell it?	Yes
Can I repair it, including the lock?	Yes — repair
Can I rebuild one from scrapped units?	No — reconstruction
Can I manufacture the blade geometry?	Yes — that patent expired
Can I manufacture the locking mechanism?	No — in force
Can I make something that looks the same?	No — design patent in force
Can I make a functionally identical product that looks different?	Yes, if it avoids the locking claim

Three numbers, three different answers. The expired one restricts nothing, the utility one restricts the mechanism, and the design one restricts the appearance only.

Twenty minutes of free lookups produced all of it. The marking alone would have suggested the whole appliance was protected.

If you want to make something similar

A different question entirely, and exhaustion does not help.

Step	Why
Read every independent claim	Scope lives there
Compare element by element	One missing element defeats literal infringement
Check the prosecution history	Narrowing limits how broadly claims are read
Check for pending continuations	New claims can still be written
Check the family for foreign equivalents	Rights are national
Get an opinion before launching	Defence against enhanced damages

Adding features never avoids infringement. Almost all claims use "comprising", which is open, so a product containing everything claimed plus more still infringes. See infringe the patent.

Buying used and refurbished

Scenario	Position
Buying second-hand from a legitimate first owner	Exhausted — fine
Buying refurbished	Generally fine, if repair not reconstruction
Buying parts to repair your own unit	Fine
Buying a unit assembled from scrapped parts	Potentially infringing
Buying a counterfeit	Infringing, plus trademark issues

The chain matters. Exhaustion depends on the first sale having been authorised, so a second-hand item originally sold by the patent holder carries clean rights however many times it has changed hands since.

Refurbishment sits on the repair line. Replacing worn parts and reselling is generally permitted; assembling units from spent components is not.

Products marked with foreign patents

Marking	Means
A US number	US rights only
An EP number	European rights, no US effect
Multiple country numbers	A family, filed in several markets
A number with no country code	Ambiguous — check
A virtual marking page listing several countries	Read the page

A foreign patent number on a product sold in the US restricts nothing there. Rights are national, and a European patent gives no US rights whatever.

Numbers repeat across countries, so a bare number without a country code is genuinely ambiguous. US 9,000,000 and EP 9,000,000 are unrelated documents. See patent number.

Patented products: the checklist

Treat the marking as a starting point. It says a patent exists, not what it covers.
Read the independent claims if the coverage matters to you. They are free to read.
Check maintenance fee status. Markings outlive patents, and 58.6% lapse early.
Buying from an authorised source exhausts the rights in that item — use, resell and repair freely.
Do not confuse repair with reconstruction. Rebuilding a spent article is making a new one.
Ignore post-sale single-use restrictions as a patent matter, but check whether you agreed to them contractually.
Authorised foreign purchases exhaust US rights in that item since Impression Products.
Check the prefix. A D-prefixed design patent covers appearance only.
Unmarked does not mean unpatented. Marking is optional.
If you want to build something similar, that is a different analysis — compare element by element and get an opinion before launching.

Common questions

What does it mean if a product is patented?

That at least one claim of a granted patent covers something in it — usually a specific feature rather than the whole product. The marking tells you a patent exists; only the claims tell you what is actually covered, and they are publicly readable.

Can I resell a patented product I bought?

Yes, if you bought it from an authorised source. Patent exhaustion means the first authorised sale exhausts the holder's rights in that item, so using, reselling and repairing it are all permitted. Exhaustion attaches to the item, not to the design.

Can I repair a patented product?

Yes. Repair is permitted, including replacing worn parts. What is not permitted is reconstruction — rebuilding the article essentially anew, which amounts to making a new infringing product. The line is fact-specific.

Are single-use restrictions on a patented product enforceable?

Not as a patent matter after an authorised sale, following Impression Products v. Lexmark. Exhaustion applies regardless of restrictions the seller attaches. Such terms may still be enforceable as contract obligations between the parties.

Can I import a patented product I bought abroad?

If the sale abroad was authorised by the patent holder, US rights in that item are exhausted and importing it is permitted. Impression Products confirmed international exhaustion. If the item came from an unauthorised maker, importing infringes.

Does a patent cover the whole product?

Rarely. Most patents claim a specific mechanism, composition or feature. A product listing four patent numbers is usually covered by four narrow claims addressing four features, not by four patents on the entire article.

How do I find out what a product's patent covers?

Take the number from the product, its packaging or its virtual marking page, look it up free in Google Patents or USPTO Patent Public Search, and read the independent claims. The title and abstract have no legal effect on scope.

Is a product still patented if the patent expired?

No. Once a patent expires the invention is in the public domain. Markings frequently outlive the patents they name, so a number on an older product may refer to something that lapsed years ago. Check status in USPTO Patent Center.

Can I make a copy of a patented product for personal use?

Technically that infringes, since making and using are both infringing acts and US law has no general personal use exception. In practice it is almost never pursued because the damages would not justify the cost.

What is virtual marking?

A web address printed on a product instead of patent numbers, leading to a page that maps products to patents. Permitted since 2011, it is easier to keep current than moulded numbers and is now the standard approach.

Does buying a patented product license me to make more?

No. Exhaustion applies to the item you bought, not to the technology. You may use, resell and repair that unit; making additional units infringes just as it would have before you bought anything.

What if a product is marked with an expired patent?

Continuing to mark with an expired patent is expressly excused from false marking liability where the patent once covered the article. For you as a purchaser it simply means the marking no longer indicates any live restriction.

Patented: definition and what it actually means

What patented means in law, why it is not the same as patentable or patent pending, what a patented product owner can and cannot do, and how to verify a claim that something is patented.

Patent marking: rules, damages and false marking

How patent marking affects damages, what constitutes constructive notice, how virtual marking works, the false marking penalty, and who has to mark what.

What it takes to infringe a patent

What legally counts as infringing a patent — the all-elements rule, direct and indirect liability, the acts covered, the defences available, and why similarity is not the test.

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