Prime-Line B 640 Adjustable Spring Tension Roller Assembly 1 in Dia Roller 1/4 in W Roller Polyethylene Roller Steel

This roller assembly with M shaped tension spring with a 1 in high density polyethylene ball bearing roller is used by several patio door manufacturers. The heat-treated tension spring is 2-5/16 in L and shaped like an M giving it the tension needed by the screen door to slide properly.