Are you having trouble sliding your screen door open or closed? Have you checked your rollers/roller assemblies? Don’t replace the entire door. For a fraction of the cost of a new door, replace those worn-out rollers. This insert style sliding screen door assembly has a high density polyethylene housing with a high density polyethylene roller insert. It is used on the Academy Uni-Fit screen doors. The roller is a 1 Inch high density polyethylene roller and is used on the top or the bottom of the door. Easy to install by inserting into the open U-shaped frame and inserting the screw. For steel ball bearing see Prime-Line part B 624. Order yours today and have your door slide like new.