For 1/8” to 1” and 6 mm to 12 mm O.D. tubing. Open-side type which slips over tube at any point. Makes smooth, tight radius bends up to 180° with minimum effort. No scoring or flattening of tubing. Calibrated to show angle of bend. Wide hook grips tubing securely. 11/16" radius to center of tube. Conforms to Federal Specification GGG-B-191a Type III, Class 2.