LFR5201-10NPP 12mm ID x 10mm U-Groove Track Roller BearingLFR5201 10NPP U Groove Track Roller Bearing 12mm ID Rubber sealed 10mm U groove roller for rail and guide systems The LFR5201 10NPP is a U groove track roller bearing with a 12mm inner diameter, designed to roll along round or square rails with smooth precision. Its sealed on both sides to keep debris out and pre lubricated for long lasting motion. Sold as one bearing. Inner diameter: 12mm U Groove width: 10mm Outer diameter: 35mm Width: 15. 9mm Load