This is a bottom mount roller assembly for mirrored wardrobe doors. Used on Crest Door and a variety of other mirror doors. Roller assembly installs up into the bottom of the metal framed mirror door. The tab on the back end of the housing allows a screw to hold it in place while the adjusting screw can be accessed through a hole below the installation screw. The 1-1/4 in. concave nylon ball bearing roller allows the metal framed mirrored door to roll smoothly and effortlessly on its track.