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
BALL and ROLLER BEARINGS POPULAR SIZE
1pcs U groove / V groove steel wheel wire rope crossing roller 10/12*58*18mm 6201 bearing guide wheel|Door Rollers| - AliExpress
DURA-LIFT Ultra-Seal 2 in. Nylon Garage Roller with Sealed 13-Ball Bearing and 4 in. Stem (10-Pack) DLRS13 - The Home Depot