Oster uses cryogenic technology to create their hardest blades ever. Material changes have been made to remove stress from the blades and cooler operation. Cryogen-X are the coolest running blades Oster offers. They stay sharper longer, and withstand repeated sharpening for unsurpassed longevity. Sharper blades glide through hair with less effort, saving you and your clipper from unnecessary fatigue and wear. Blades fit Oster A5 and other A5-compatible clipper.