Yamaha Digital Violet ME-55VT Clip-on Metronome,

Clip-on type that can be attached to music stands or clothing. Easy dial-type volume control. Display/LED indicator (1 location, red) Sound source: Reference pitch A, B♭ (440Hz, 442Hz) Power source: CR2032 lithium battery x 1 (Battery life: approx. 50 hours)