Manual number:8354+8351Product major function & usage:Leading the gears to spin and transfer the energy from the motor to achieve smooth steering performanceMajor advantages of upgrading to this product:1. Harden steel #45 plus nutrified and hardening process, more durable to use2. CVD design for larger steering angle and smooth performance.Other special notes and comments:Length from each end of dog bone to mid-point: 33mmSuitable Model:1/10 4WD FORD GT4-TEC 2.01/10 4WD 4-TEC 3.0 CORVETTE STINGARY-93054-4