Machinists' Boxed Half-Round FileUsed 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. Applicable Materials: Most Metals; Cross Section Shape: Half Round; Cut Type: Second Cut; Length: 12 in; Quantity: 6 per box; Style: American Pattern; Tool Shape: Straight; Tooth Pattern: Curved - Double Cut, Flat - Double Cut; Weight: 0.90 lb.