Is this the only US post office equipped with a life jacket?

The town of Cranberry Isles, which is composed of five islands, has two post offices. One, the Islesford Post Office, is in the Islesford Market on Little Cranberry Island (Islesford is the name of the village, but it's often used to refer to the entire island). Picture here is the other

one, the Cranberry Isles Post Office, on Great Cranberry Island. Longtime postmaster Eileen Richards jokes that "it's the only post office in America equipped with a life jacket.”