These are two Homing Keycaps originally designed by MNT and FKCaps for your MNT Reform Laptop or the MNT Reform Standalone Keyboard. The homing caps feature a tactile ridge that you can feel to identify the F and J positions on the keyboard (in the QWERTY-US and similar versions).

These keycaps are designed for the low profile Kailh Choc switches.

The body of the caps is injection molded translucent ABS with a thin PU coating. The caps are designed for backlighting and can be lettered by selectively removing parts of the PU coating with a standard CO2 laser engraver.