Double Bearing: The pulley is equipped with two small ball bearings that allow it to rotate smoothly and reduce friction. Material: Made of high-quality galvanized steel, sturdy, durable, and corrosion-resistant. The pulleys are treated and have a burr-free surface to protect the rope and your hands. Small Pulley: Length*Width*Height=55*44*41mm. The pulley diameter is 30.5 mm; its width is 25 mm; the maximum groove width is 15 mm, the minimum groove width is 3.8 mm, and its depth is 8 mm. The pulley is suitable for diameters from 1 to 8 mm. The maximum load is 200 kg and the safety load is 50 kg. Pulleys can be used for guiding ropes, lifting objects, cable winches, or for light sliding doors. Quantity: 4 pulleys