Brand: AIM Sports
This round insert is designed specifically to fit into a rubber button cover on an AiM PDM keypad (Part Nos. MC-KEY08 or MC-KEY12, sold separately). The back of the insert has a flat tab which fits into the cross-shaped slot on the keypad button. Sold individually.
This "Diff Lock, Rear" insert has a black background with a simple "rear differential lock" icon (a pictogram of 4 wheels with the front wheels turned and an X on the center of the rear axle).