Standard Tolerance Saw Cut Rectangle/Flat Stock is a more economic option to the ground flat stock when you don’t require precision tolerances. It will be oversized to finish to the listed dimensions. S7 Steel Rectangle/Flat Bar S7 is an oil or air-hardened tool steel that exhibits excellent high impact toughness and strength. Furthermore, S7 is a premium shock resistant tool steel which provides a unique combination of machinability, exceptional toughness, ease of heat treatment and minimum distortion.