The combination of the nylon wheel and internal sealed metal bearing ensures that the wheel rolls smoothly and noiselessly, preventing the annoying squeaking common with lower-quality pulleys. The pulley is crafted from high-quality, solid nylon, which is wear-resistant, waterproof, and more durable than conventional plastic wheels. The metal bush protects the internal structure and grease from corrosion, dust, and impurities, contributing to a longer service life. These heavy-duty pulleys are designed to withstand significant tension and can support consistent working loads of up to 1,000 lbs (model dependent), ensuring high safety performance and stability during intense workouts.