This is the O.S. New $176.39 (37% off). Max .37 SZ-H Ring Helicopter Engine. (Two year limited warranty):. Features: * Premium performance for 30-sized machines, from extreme aerobatics t stable hovering.:. * Same mounting pattern and muffler dimensions as the .32 SX-H, fo easy installation in most 30-size helis.:. * Re-engineered crankshaft reduces vibration resulting in smooth powe across the entire RPM range.:. * 20M carburetor with Idle Needle positioned on same side as Mai Needle for easier adjustments.:.

This is the Pro .39H Ringed Two Stroke Helicopter Engine from Thunder Tiger.:. New $129.99 (23% off). Features: * Fits all popular 30 size helicopters with gear ratios between 9.1: to 9.8:1.:. * Developes peak horsepower at 16,000-18,000RPM.:. * Crankshaft supported by two ball bearings.:. * Lightened hypereutectic machined Al-Si ringed piston.:. * Two-needle air-bleed carburetor.:. * XC2 (extreme composite) cylinder liner coating with a criss-cros pattern etched on the sleeve wall.:. * Rear reinforced resin cage ball bearing support.:. * Three year limited warranty through Hobby Services beginning at dat of purchase.:.