Blades for Oster A-5 clippers and other brands that use the same replaceable blades The cut indicates the uniform length of hair which will be left when you use the designated blade. Oster Cryotech Blades are freeze tempered. As the blades are frozen to 300 degrees below zero, the steel molecules become denser, which increases the steel's durability. To the grooming professional this means that not only do Oster blades start out sharp, they stay sharper longer.