Self-adjusting tensioner Arm Rotation 70 Degrees For Chain Number Not Applicable For V-Belt Size B Pulley Outside Diameter 4 in Maximum Tension Force 42 lbf Arm Length to Hole Center 4.5 in Arm Material Aluminum Features Automatically Take Up the Slack and Avoid the Risk of Over-Tensioning Drive Components to Enhance Overall Drive Operating Efficiency Housing Material Aluminum Includes RT3000 Tensioner VX0285 Pulley Minimum Tension Force 0 lbf Mount Hole Diameter 33/64 in