Keyguard for the original Apple Magic Keyboard for iPad.  This is not the Magic Keyboard for the Mac, and it's not the Apple Smart Keyboard, and it is not the current model of the Magic Keyboard.  It's the original Magic Keyboard for iPad that worked with the 12.9 Pro 2nd Generation, and perhaps later for the iPad Air 4 10.9.  It is distinguished by its smaller, more rounded key caps.  See the pictures to be sure it's the one you want.

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

No attachment method is provided with this keyguard.  You'll need to attach it yourself with something like double-sided tape, Velcro, or mounting putty (Blu Tack, etc.)

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.