Does it matter whether the letter asserts a design patent or a utility patent?

How should I review a utility-patent allegation?

Obtain the asserted claims and an explanation of how their limitations correspond to the accused product or process. If the sender relies on equivalents, ask for that theory too. Warner-Jenkinson Co. v. Hilton Davis Chemical Co. requires equivalence to be assessed element by element.

How should I review a design-patent allegation?

Obtain the complete patent drawings and clear views of the accused product. Under Egyptian Goddess, Inc. v. Swisa, Inc., design-patent infringement uses the ordinary-observer test, informed by the prior art where appropriate. Do not reduce that test to counting a few similar features.

Why does the distinction matter for money?

Section 284 provides compensatory patent damages, including at least a reasonable royalty. Section 289 supplies an additional design-patent remedy tied to total profit on the relevant article of manufacture, with a bar on duplicating that profit recovery. The remedy claimed should be identified rather than assumed from the demand amount.

What should the response request?

Ask for the patent numbers, accused product versions, asserted utility claims or design drawings, and the basis for the requested relief. Keep the comparison for each patent separate.