Clear Plastic Discs (Pack of 20) Features: Glass Tops Direct Clear Plastic Discs, also called "desk buttons" are practically invisible underneath the glass table top. These provide excellent protection for all surfaces. Primarily used with 1/4" or 3/8" thick glass this is often used to protect a surface from scratches due to everyday use. Plastic Discs provide a stable cushion between surfaces and are easy to move since there is no adhesive. Our pack contains 20 clear discs. They measure approximately 3/4" diameter and are 1/32" thick.