Description FULLY BACK-LIT KEYBOARD With an LED under each cap, the POSEIDON Z Illuminated is a fully back-lit keyboard, offering 4 levels of adjustable brightness via the Fn (function) + F11/F12 keys. FASTER RESPONSE MECHANICAL SWITCHES The leading mechanical blue/brown switch actuates a bit after the tactile feedback of the key, but the Tt eSPORTS Certified Mechanical switches actuates earlier and closer to the tactile feedback. Offering a more accurate feel and faster response time than the other more commonly found mechanical switches.