Amazon.com: Letool 4pcs U type groove pulley nylon Guide Pulley Rolling Bearing U Groove Roller Wheel 8x40x20mm for Driving Mechanical Equipment, or Used in Doors and Windows : Industrial & Scientific
U V Round Groove Nylon Roller 608zz Ball Bearing Wheel For Sliding Door - Buy Ball Bearing Wheel For Sliding Door,Nylon Roller Wheels,Roller Wheel For Sliding Door Product on Alibaba.com