B610 Material: 1" Steel Ball Bearing Features: -Spring tension roller. -Wheel with center groove, used as a top and bottom roller. -Spring type: Wire-spring. -Width: 0.25". -Edge type: Concave. -Dimensions: 5.44-6.44" H x 1.75-3.81" W x 0.63-3.81" D. b515 Installation b541 Installation b610 Installation