Tandem 1-1/2″ steel roller diecast hous

Extra heavy-duty plain back, tandem roller assembly used by kawneer on their heavy doors. It has an in-line tandem inner housing with 1-1/2" concave or grooved steel ball bearing rollers set in a heavy-duty diecast outer housing with rear adjustment. The housing is 1-13/16" tall and 1-1/8" wide and is held in place by screws from the top as well as the end part# 131244