Sliding, Rolling Gate Guide Roller Black UHMW Rollers Rubberized Hard Plastic Sliding Gate Roller Guide with Bracket ( Bracket to Bracket measures 3") Heavy duty bolt on or weld on bracket Uses 1/8" thick x 3 1/2" tall C bracket for mounting Sealed ball bearings for smooth rolling 2 3/4" offset from mounting surface - 2 1/4" diameter Never needs greasing or maintenance, Easy installation