This newly revised outboard engine is for racing boats up to 70cm in length It provides maximum performance combined with good design . The housing is made of high quality and extremely durable plastic. A flexible shaft with aluminum adaptor ensures as low friction as possible and safe driving at high speeds. The flex shaft can be easily removed and serviced . Technical Specifications: Propeller diameter 31 mm Propeller recording M4 Total height 160 mm Overall width 48 mm Total length 120 mm Motor brushless outrunner type 2836 3600kv Recommended battery 7.4V LiPo 2S 3300-4200 mAh Maximum voltage : 3S / 11.1 V 60A Speed Controller Required