Rock Exotica Omni-Block 1.5" Pulley - 0.75" Shackle Top Weight: 10.7 oz (303 gm) Breaking Strength: 2 x 18 kN=36 kN Working Load: 2 x 4kN=8 kN Max Rope Diameter: 13 mm Sheave Diameter: 1.5" (38 mm)