This is a S280 Gearbox with 3.5:1 Gear Ratio and uses Standard Bushings. For use with the Great Planes Park Flyers. FEATURES: Designed for low noise and low maintenance, Park Flyer gearboxes used with 280-sized motors get the maximum climbing power and flight time from each mAh. A brass pinion gear is used for strength and a nylon main gear for quiet, low friction operation. Compatible with APC"s light, durable Slo-Flyer Propellers Economical bronze bushings for long-lasting sport use Lightweight, fiber-reinforced, sealed gear case keeps out dust and debris as well as resists damage. INCLUDES: One assembled S280 gearbox 3.5:1 ratio One brass 13 tooth pinion gear Three 2x6mm self-tapping gearbox mounting screws One mini tube of Thread Locker to secure pinion to the motor shaft REQUIRES: Prop adapter 3mm shaft for APC propeller, use GPMQ4959. Install pinion onto motor shaft, then into the gearbox Assembly of unit onto the airplane SPECS: Overall Length: 37mm (1.5")(back of motor shroud to front of case) Overall Height: 35.8mm (1.4")(motor shroud and gear case) Motor Shroud Inner Diameter: 24mm (.9") Gear Case Outer Diameter: 30.5mm (1.2") Mounting Hole Flanges On-Center: 33.3mm (1.3")(three, evenly spaced) Shaft Length: 7.3mm (.3") Shaft Diameter: 3mm (.12") Weight: 15 grams COMMENTS: For T-280 motor, use GPMG0300. JXS 12/01/00 ir/jl