This is a S280 Gearbox with 3.5:1 Gear Ratio and uses Ball Bearings. / 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 / Precision ball bearings for all-out performance / 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 (GPMG0240) / 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 GPMQ4600. / 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")