Amazon: guide roller
ALEKO Side Roller for Sliding Rolling Gate Guide Roller Black Guide with Bracket, 2-Inch. 4.6 out of 5 stars. 76. Skelang 6" Slide Gate Guide Roller with Post Welded Bracket, UHMW Hard Nylon Sliding Rolling Gates Guider, Heavy Duty Sealed Ball Bearing Side Roller Assembly (White - 6 …