O.S. MAX 37SZ-H Ring w/o Drive Wash (L-OS14000) Following on from the concept developed in the 70SZ-H, the latest 37SZ-H brings a new level of performance to 30-class helicopters. Just about everything has been changed compared to the 32SX-H in the pursuit of power & control. That super-rigid crankcase contains a highly developed, ringed piston/liner set & optimised crankshaft for the right combination of power & smoothness. The new carburettor has been purpose designed for precision control & is capable of being operated by push-pull linkages if required. This is the perfect engine to compliment your new Hirobo Sceadu Evo & move your flying on to a new level. Specification: Weight: 293g 10.33 oz Displacement: 6.07cc 0.37cu in. Bore: 20.5mm 0.807in. Stroke: 18.4mm 0.724in Power Output: 1.4PS@18000 RPMPractical RPM: 2000-21000