This is a Roland DP-2 footswitch for keyboards, guitar, effects etc. 1/4" plug, normally closed 'mono' switch.
Roland DP2 Damper Pedal, Black
Roland Jazz Chorus JC120 Original Footswitch
Roland DP-2 Damper Pedal Keyboard Footswitch Sustain 1/4" Mono Jack
MILISTEN 4sets Pedal Footswitch Toppers with Rubber Pads for Guitar Effects Pedals Durable Aluminum Alloy Protection for Footswitch Buttons
20Pcs Pedal Footswitch Guitar Pedal Footswitch Topper M3V59173