This keycap is made of ABS plastic. When exposed to sunlight or fluorescent or black light, the keycap will absorb the energy. After that, when it comes to full dark, the stored light will gradually emit and the keycap glows pale yellow-green so it will glow in the dark. Fit on Row 1 which includes the Esc, F1-F12, etc (check the keycap size chart); and compatible for Cherry MX / Gateron / Kailh / Razer / others MX clone mechanical switch. Designed for non-backlit mechanical keyboard especially, but you can put on backlit keyboard too.
* Due to the light and screen difference, the item's color may be slightly different from the pictures.