Torque link uses a coil spring to absorb engine torque and increase traction to rear tires. The dual shaft design allows engine torque and brake bushings to be adjusted separately. Unit comes with two purple (60 durometer) engine torque bushings and one red (87 durometer) brake bushing. Other bushings are available for additional tuning options. Unit requires a 5" O.D. x 6-5/8" or 7" tall coil spring, sold separately. Unit is 17" long overall and most commonly used with two 3/4"-16 rods ends (1-RH Female and 1-LH Male) and a 3/4" suspension tube. Subtract 20" from center-to-center of the chassis mounting distance to determine required tube length. 9.3 lbs. without spring.