These stark and elegant Black Windowed Lamp R4 Keycaps are made of opaque black plastic with a small cutout in the south-center edge that wraps around the top and bottom. The cut-out has a clear plastic window to allow an LED installed under the switch to glow through. They add a bit of the je ne sais quoi to your keeb or macropad build and are somewhat rare to find. https://elecena.pl/product/18974840/black-windowed-lamp-r4-keycap-for-mx-compatible-switches 2021-07-01 https://elecena.pl/product/18974840/black-windowed-lamp-r4-keycap-for-mx-compatible-switches 2021-12-07