This is a Variable Rate Air Control Kit from Robart for Any Pnuematic Retract System. This Allows the modeler to Control the rate at which the Retracts go Up and Down. This can be used with either a 3 gear or a 2 gear setup. This Air Control Kit comes with Everything Needed to Complete Any of the Robart Pneumatic Retract Setups. INCLUDES: One Instruction Sheet One Variable Control Valve Five Tee Fittings-Nylon One Air Fill Valve One 5ft of Purple Tubing One 5ft of Red Tubing Six Retaining Nuts One Small Air Vessel (Tank) SPECS: Air Control Valve Length: 2" Width: 1/2" Air Vessel Length: 6 1/2" Diameter: 1-3/4" REQUIRES: Pressure gauge, ROBQ0173 COMMENTS: Again this kit will work with any manufacturer's pneumatic retract set.