I had to close the bottom of the key somehow.Firstly I planned to cover it with some kind of rubberized surface to make it anti-grip when remove it from the USB slot. I always try to make my project as genuine as possible, so why not to use a genuine apple part again? I removed the apple pro keyboard sticker from the back of it, cut it to the right size, and place it. Hence it is 19 years old still self- adhesive anyway, so saved some glue too! Hmm, 80's Cupertino plastic... Color match!