4 Pack Sliding Screen Door Tension Spring Fits for Columbia and Uni-Fit Doors, Replaces B 649 and B 704 Used on Both Top and Bottom, 1" Concaved Steel Ball Bearing

Compatible with Columbia Uni-Fit series doors as well as a variety of other sliding screen door manufacturers for replacing similar spring tension rollers. | It has a flat steel tension spring and comes with a 1" steel ball bearing roller. | The flat steel spring end catches onto the inside of the door frame while the flat edges of the two tabs extending out in front of the roller restrict the roller from retracting too far up into the door frame as it rolls. | The assembly inserts into the bottom or top of the sliding screen doors.