For greater durability and consistent performance in the Powerglide, TCI introduces the Dual Ring Servo Kit. This kit uses two Teflon sealing rings in place of the original single design or dual rubber ring designs offered elsewhere. This doubles sealing effectiveness and prevents excessive leakage which can reduce band apply force. This feature also reduces vehicle rocking when the Trans-Brake is applied and provides additional stability in low gear. Perfect for the Super Class racer seeking positive Trans-Brake engagement when staging.