Grow-U-Groove Pulley Roller Guide Wheel 8x40x20.7mm 4pcs 0840UU U Type - Walmart.com
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
4mm Bore Bearing with 13mm Pulley U Groove Track Roller Bearing 4x13x7mm – VXB Ball Bearings
U Groove Polyurethane Wheels - Wear Resistant Wheels! - Plan Tech
UGS-5022R - 5" x 2-1/4" U-Groove Wheel - caster wheel distributing company, heavy equipment, caster wheels online