This keyguard fits the Azio MK Retro USB keyboard with the round keys.  If you have any other version of the Retro keyboard, you can order a keyguard for it as a custom keyguard.

This item does not come with a keyboard. This is to order the keyguard only. 

The keyguard is attached to the keyboard with Dual Lock™ recloseable fasteners (included).  

Material - The keys are just under 1/8" high, so if you pick an 1/8" material, the top of the keys will be just below the surface of the keyboard.  Most people prefer a material of 3/16" or greater, to give a little depth to the holes, requiring a more deliberate touch. 1/4" materials make for even deeper holes. A popular choice is polycarbonate, which has a lifetime guarantee against breakage and nice, bevelled edges which make the keyguard softer to the touch.