This keycap is made of durable PBT plastic and featuring dye sublimated legends. Fit on Row 4 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.