There are two carbon steel ball bearings inside the pulley, which can reduce the friction of the wheel. The pulley rotates more flexibility and does not make noise. Made of stainless steel, rustproof, corrosion resistant, outdoor use can also prevent the pulley from corrosion. Compared to other pulleys, the pulley wheel support plate is thicker, the wheels are stronger, and the bearing capacity is stronger. Application: steel cable wheel, transmission equipment, industrial pulley. For long lasting durability against heat, shock and corrosion Product Description Features: Material: iron + bearing steel. Color: titanium. Maximum load: 250 kg. Inner diameter: 8 mm. Outer diameter: 40 mm. Thickness: 13 mm. Groove width: 10 mm. Groove depth: 7, 5 mm. Radian: R = 5 mm. Dimensions: 40 x 13 mm. Weight: 99 g.