ODK3550 Features: * Used on concave, cinvex and flat surfaces * Rounded on 1 side, flat on opposite * Backs of all half-round bastard files are double-cut * Backs of all 4 and 6"" files are single-cut * Backs of all half-round second-cut files are longer than 6"" are double-cut * Cross Section Shape: Half Round * Tool Shape: Straight * Style: American Pattern * Applicable Materials: Most Metals