It is a Koss brand volume control for the remote. In case I ever want to use earphones with the remote. I used extra strength two sided tape to attach it.

Corvallis, OR
Detectors:
Tesoro Bandido II Umax (2)
Tesoro Outlaw
Whites MXT Pro
Minelab Equinox 800
XP Deus with 9” and 11” X35 coils
XP ORX with 5x9” and 9” hf coils (My traveling detector)
Whites XLT