The X-keys Stick uses a low profile tactile switch with a square stem. This keycap is only compatible with X-keys Stick Models.
The pack of 8 beige Keycaps for XK-16 Stick from X-keys use low-profile tactile switches with square stems. The X-keys have a backlit window at the base, which allows the blue LEDs of the XK-16 to illuminate each key from the back.
Single replacement keys with a backlighting window in the base which allows the blue LED to illuminate the key legend from the back.