【4 x 1.2" V-Groove Pulleys】The snatch block uses a 25mm thick double ball bearing design with high-strength bolts and locking nuts, effectively reducing vibration, operating smoothly, and minimizing noise. Allows the door to slide easily in or out for flexible sliding. The V-groove fits perfectly with the track and reduces vibration. 【Sturdy and Durable】The roller is an all-steel structure, made of solid steel castings. The solid structure is wear-resistant and high-temperature resistant, and color-plated to prevent rust and corrosion. Temperature range: -45°F to +180°F. Load capacity: 210kg. The load capacity will be affected by different installation angles and installation on different material surfaces, such as walls, wood, and metal. 【Suitable Projects】The lifting pulleys are suitable for sliding doors and windows, inverted rails, factory gates, telescopic doors, garage doors, trolleys, iron gates, rail gates, roller shutter doors, garden gates, container rails, warehouse elevators, lifting blocks, small-diameter racks, and other indoor or outdoor projects. The double bearings slide stably and smoothly, making it easy to push the gate. 【Wide Application】The orbital roller is not only suitable for daily use, but also for professional use. Widely used in automobiles, automated production lines, and various general machinery and equipment. Rope pulleys, garages, clotheslines, and pulley systems for indoor and outdoor use. You can also DIY home fitness equipment, fitness accessories, and pulley machines. 【Easy to Install】Each pulley is equipped with 4 mounting holes, which can be easily fixed by clamping or welding, making it practical and convenient. The small metal pulleys can be used with wires, ropes and cables and have extra load capacity. The sturdy top makes it easy to handle the rope and the double roller bearings ensure stable sliding for good rope guidance.