This is a .61 size Airplane Engine by Thunder Tiger. It is made in Taiwan and comes with a 3-Year Limited Warranty. FEATURES: Dual ball bearing-supported crankshaft Schnuerle porting ABN piston/cylinder assembly Forged aluminum connecting rod with dual bushings Unique "squared" cylinder head design has more surface area than most conventional cylinder heads, for cooler runs Twin-needle carburetor INCLUDES: One Engine with glow plug One Expansion-Style Muffler w/Pressure Fitting & Rotatable Outlet One Wrench Set One Instruction Booklet and Decals REQUIRES: Prop, engine mount, fuel filter, and fuel (Thunder Tiger recommends fuel with castor oil). SPECS: Displacement: .609 cu in (9.97cc) Bore: .9251" (23.5mm) Stroke: .9055" (23mm) Power Output: 1.8 HP @ 13,000 RPM Maximum RPM range: 2,000 @ 17,000 Practical RPM range: 2,500 @ 14,000 Weight (w/muffler): 26.1oz (740g) Crankshaft thread size: 5/16-24 Crankcase width (for engine mount): 1.69" Overall height: 4.13" (105mm) Overall width (w/mount flanges): 2.48" (63mm) Overall length (backplate to front of drive washer): 3.74" (95mm) Recommended prop size: 11x9, 11x10, 10x11 (aerobatic) 11x8, 12x7, 12.5x6 (sport and scale) 11x7 (break-in) 8/28/95eke ir/jl updt jxs 9/02/03 updt jxs 04/20/10