<h3>Key features</h3><ul> <li>16mm 0.79inch SBR16 UU ball bearings sliding blocks, made of aluminum alloy and bearing steel, heavy duty and sturdy</li> <li>High Quality - With excellent motion ball, it moves smoothly with low friction. You can use it for a long time.</li> <li>Size - Shaft diameter: 16mm. Overall size: 1.78” x 1.3” x 1.78”</li> </ul><p>Free shipping included. 30-day hassle-free returns.</p>