Lottia pelta is one of about 20 intertidal limpets occurring locally.   The characters given in the introduction may help distinguish it from other species but detailed descriptions are required to be reasonably certain of your identification.

Limpets are also members of the class Gastropoda which includes coiled snails,  abalone,  and key-hole limpets as well as shell-less sea slugs.

Another kind of limpet covered by a pink sea weed on which it feeds