This is a Robostrut Ready Tri Gear Set with 3/16" 90° mains, 5/32 wire 90° Rail Mount Nose, Robart 520W1 Retract Set with Air Kit. FEATURES: The 520 Series Retract offers a high performance air up and spring down. Steerable nose gear INCLUDES: 521W1 Retracts Air kit: -Small air tank -Two 3/16" wire landing gear -5/32" nose gear wire -Control Valve -Fill Valve -Air Supply in fitting -Three T-fittings -Straight servo horn -Orange air line Instruction sheet REQUIRES: Air pump (ROBQ2363) Servo Link rod assembly to the Control Valve SPECS: Main Retracts: Length: 3-5/8" (92mm) including air cylinders Width: 1-3/4" (45mm) Depth: 1-1/2" (38mm) Nose Retract: Length: 3-13/16" (97mm) including air cylinder) Width: 1-3/4" (45mm) Depth: 1-9/16" (40mm) COMMENTS: If the Robart Axle Adapter with 3/16" Axle for 5/32 Wire Struts is needed, order ROBQ0658 For the Adapter with 3/16" for 3/16 Wire Struts, order ROBQ0659. jxs 8/09/05 ir/jxs