uxcell 12mm Inner Diameter Deep Groove 6301ZZ Ball Wheel Bearing Product Name : Groove Ball Wheel Bearings;Type : 6301ZZ Materal : Carbon Steel;Outer Diameter : 37mm/1.45" Inner Diameter : 12mm/0.472";Thickness : 12mm/ 0.472" Color : Silver Tone;Weight : 60g Package Content : 1 x Groove Ball Wheel Bearings