This is the O.S. Max .25LA-S Natural Finish Control Line Engine with Muffler. FEATURES: LA-S series engines Control Line engines replace the Carburetor with a Venturi that keeps the engine running at a constant speed Remote Needle Valve reduces chance of injury from spinning props Nylon backplate mount and ratchet spring help hold settings against "creep" caused by vibration An O-ring helps seal the needle from fuel and air leaks Heavy-duty webbing reinforces the one-piece crankcase in high stress areas. TWO YEAR WARRANTY against manufacturing defects in parts and workman- ship INCLUDES: One .25LA-S Control Line Engine with #E-2030 Muffler Two 2.5 x 24mm Phillips head muffler mounting screws #A3 Glow Plug (OSMG2690) Decal Sheet Instruction Manual REQUIRES: Fuel: 10% to 20% Nitro and 18% lubricant content is recommended Prop: Break in: 9x6 Aerobatic and Sport: 9x6, 10x5 SPECS: Displacement: 4.07cc (.249 cu in) Bore: 18mm (.709") Stroke: 16mm (.630") Output: 0.6 PS, 0.59 HP @ 15,000 RPM Practical RPM: 2,000 - 16,000 RPM Weight: 185.5g (6.54oz) Crankshaft size: 1/4-28 Distance between mounting tabs: 1.89" (48mm) Distance between mounting holes on opposite side: 1.46" (37mm) Distance between mounting holes on same side: .59" (15mm) Width of crankcase below mounting tabs: 1.10" (28mm) Height from bottom of crankcase to top/cylinder head: 2.93" (74.4mm) Length from end of crankshaft to backplate: 3.43" (87.1mm) Needle Settings: High Speed: 1.5 turns out from fully closed Mixture Control (low speed): Tip of the needle half way across the small hole in the front of the carb tlw 6/22/07 ir/jxs updt lmm 4/6/09