This is a Set of 85° Heavy Duty Retracts are for Planes 5-10 Pounds. FEATURES: Heavy Duty Struts, 3/16" diameter wire INCLUDES: Two 85° Non-Rotating Main Pneumatic Heavy Duty Retracts Eight S/T Flat Head Screws One Instruction Sheet SPECS: Retract Unit: Width: 1.75" Length: 3.69" (including air cylinder) Depth: 1.125" Struts: Length: 7.75" x Diameter 3/16" Weight (per pair): 6oz REQUIRES: ROBQ2302 Air Control Kit (Tubing, Valves, Air Vessel) ROBQ2363 Hand Pump with Gauge Wheels Axles, use GPMQ4282 ROBQ2395 Quick Connector (for ease in connecting and disconnecting the pump) ROBQ2389 Air restrictors (restricts air flow to the retract for a realistic movement--slows the Retract mechanism to scale speed) A standard servo may be used to operate these retracts. COMMENTS: Robostruts will not directly fit these struts, the adapter that comes with the Robostruts (ROBQ1700-1706) can be use to adapt the 3/16" struts. The struts are Not pre-bent for the wheels, the instructions show how to apply heat to bend them. Order ROBQ0659 for Axle Adapter with 3/16" Axle 4-28-93/eke ir/jl updt jxs 12/05/05