This Prime-Line N 6870 Mirror Door Roller Assembly is constructed of a steel housing and a concaved (grooved) edge, plastic wheel. The housing has 2-1/2 inch mounting hole centers, its body measures 1-11/16 inch wide and its only 7/16 inch deep. This mirror door roller assembly is most commonly used on wood framed sliding mirror doors. The wheel is constructed of durable plastic which provides for a smooth, long-lasting, quiet roll and it features a narrow concave (grooved) edge. This mirror door roller assembly mounts on the bottoms of sliding mirrored closet doors, it is adjustable once installed, and it is used by many closet door manufacturers.