Military “lights out” instrument

BUGLE

Not available

This clue plays on the military tradition of "lights out," the command signaling the end of the day when soldiers go to sleep. The instrument tied to this routine is the bugle, which famously plays "Taps" to mark lights out in barracks or at ceremonies. The word "lights out" hints at the bugle’s role in sounding the call, making it a straightforward but clever reference to the answer.