Item Type: Slide Block Material: Aluminum Alloy Inside Diameter: Appprox. 12 mm/0.5in Length: Approx. 40 mm/1.6in Width: Approx. 39 mm/1.5in Height: Approx. 27.6 mm/1.1in Package List 1 x Bearing Please allow 12cm/0.4& 8209;0.8in error in measurement. 1Surface oxidation treatment, beautiful and corrosion resistant. Smooth moving, low friction, high rigidity and long life. 2Aluminum alloy material, stronger bearing capacity. High quality bearings, exquisite workmanship, high precision. 3Surface oxidation treatment, beautiful and corrosion resistant. Prevent dust from entering and prolong service life. 4Applied to electronic equipment, packaging machinery, medical machinery, printing machinery, textile machinery, machine tools etc. 5The universal ball bearings is great for you to replace the damaged ball bearings in your devices to improve them efficiency and save energy.