Adjustment Knob Compatible Grainger Part Number 31XG57 Compatible Manufacturer Model Number SM-6T-6201 SM-6X-6180 SM-6X-6201 SM-6Z-6105 SM-6Z-6201 SM-6Z-6202 Includes Not Applicable Material Plastic Steel Number of Pieces 1 Overall Diameter 18 mm Overall Length 43 mm Overall Width Not Applicable Product Type Contact Arm Adjustment Knob