I have a handheld one—to float with me in a liferaft, etc—and it gets registered to a vessel or vehicle. Whenever I want to use it on something different, contact the federal government, advise of the new vessel ID or vehicle registration, and it’s now associated with the new one.

I don’t think it matters much since it is a beacon after all, but I think it helps in searching. Also, a lot of other details are registered along with it so they know who to send the tens of thousands in fines to if I somehow bypass all three “Are you really sure?” switches and fire the thing off inappropriately.