Annular device with battery cover

摘要

An annular device includes an annular main body, a battery mounting portion, and a battery cover. The battery mounting portion protrudes from an inner surface of the main body, and includes a first arcuate element and a second arcuate element opposite to each other. The battery cover is operable to clasp the battery mounting portion, and includes a first arcuate member and a second arcuate member opposite to each other. The first arcuate member clasps the first arcuate surface, and the second arcuate member clasps the second arcuate surface.