This is the O.S. Max .37 SZ-H Ring Helicopter Engine. (Two year limited warranty) FEATURES: Premium performance for 30-sized machines, from extreme aerobatics to stable hovering Same mounting pattern and muffler dimensions as the .32 SX-H, for easy installation in most 30-size helis Re-engineered crankshaft reduces vibration resulting in smooth power across the entire RPM range 20M carburetor with Idle Needle positioned on same side as Main Needle for easier adjustments INCLUDES: One O.S. Max .37 SZ-H Ring Helicopter Engine, with #8 Glow Plug, 20M Carburetor, instruction manual and sticker sheet REQUIRES: Muffler Heli fuel with 10%-30% nitro content SPECS Displacement: 0.37 cu in (6.07cc) Bore: 0.806 in (20.5mm) Stroke: 0.725 in (18.4mm) Practical RPM range: 2000-21,000 Output: 1.4 ps @ 18,000 RPM Weight: 10.3oz (293g) Crankshaft Size: 1/4-28