Highlights SBR Linear Guide Rail Set: SBR16-800 mm Linear motion guide rail includes 2 x 31.5 in/800 mm length SBR16 guide rails and 4 x SBR16UU slide blocks. Dynamic Load Per Block: 774 N, Static Load Per Block: 1180 N. Durable & Long-lasting: The linear rail is made of carbon steel and aluminum with a chrome-plated surface for rust resistance and high durability. Built-in 4 aluminum slide blocks and ball bearings for smooth and unobstructed sliding. Low Noise Sliding: Aluminum SBR slide blocks and carbon steel linear shaft are perfectly paired. The built-in ball bearing provides low friction movement and is smooth and not tilted, allowing you to control more labor-saving.