LFR5201-12NPP 12mm ID x 35mm U-Groove Track Roller BearingLFR5201 12NPP U Groove Track Roller Bearing 12mm ID x 35mm OD x 15. 9mm Wide The LFR5201 12NPP is a heavy duty U groove guide bearing built for linear motion systems that run on round rails or guide tracks. With a 12mm inner diameter and durable construction, its perfect for high load applications like automated conveyors, track systems, and guided transport setups. Type: U groove track roller bearing Inner Diameter (ID): 12mm Outer Diameter (OD):