Our classic Stoppers have the ideal proportions of length, width and depth to work well with most any crack. Their unique transverse taper that allows them to be placed in bottlenecks, flares and shallow seams. Extruded from soft yet strong 6061-T6 aluminum alloy, these nuts are swaged on galvanized steel cable and have rounded edges for easy cleaning. The smallest sizes (1, 2 and 3) are extruded from 7075 aluminum, which is harder than 6061-T3 so that the Stopper cannot shear or pull through the crack. Sizes 1, 2 and 3 have straight sides for maximum contact with the rock. No. 1 Weight: 7 g/0.25 oz. Strength: 2 kN/450 lbf No. 2 Weight: 8 g/0.28 oz. Strength: 2 kN/450 lbf No. 3 Weight: 15 g/0.53 oz. Strength: 5 kN/1124 lbf No. 4 Weight: 16 g/0.56 oz. Strength: 6 kN/1349 lbf No. 5 Weight: 18 g/0.63 oz. Strength: 6 kN/1349 lbf No. 6 Weight: 32 g/1.13 oz. Strength: 10 kN/2248 lbf No. 7 Weight: 34 g/1.2 oz. Strength: 10 kN/2248 lbf No. 8 Weight: 37 g/1.3 oz. Strength: 10 kN/2248 lbf No. 9 Weight: 39 g/1.4 oz. Strength: 10 kN/2248 lbf No. 10 Weight: 43 g/1.5 oz. Strength: 10 kN/2248 lbf