No slippage, with excellent adhesion properties to all lens materials and slick coatings , such as uncoated and coated CR39, Polycarbonate, Hi-Index, and Glass. The adhesive system implemented in the OptiSafe® Lens Blocking Pads  provides the appropriate amount of adhesion to prevent slippage while edging lenses, yet the pads are easy to remove leaving absolutely no residue. The OptiSafe® Lens Blocking Pads  are the ultimate solution to all your edging problems. Available in different sizes to fit metal and plastic blocks.