D1518 Features: -Door roller. -Material: Steel ball bearing. -Edge type: Concave. -Number of wheels: 1. -Housing style: K-Tab. -1.25" Steel ball bearing roller with adjustable steel housing assembly. -Replaces old-style extruded aluminum assembly. -0.75" Overall thickness at dimples. Specifications: -Housing width: 0.75" at dimples. -Housing length: 2.13". -Dimensions: 5.44" H x 3.81" W x 0.88" D. Installation