This OMH-4535-1260 motor is designed to be used in 550-600 size helis using 6S Li-Po batteries. Every piece of this motor had been designed to help reduce friction/noise and increase the power and efficiency.With a 45mm dia. this motor can easially be installed in almost all the existing 550-600 class helicopters without modifications. The shaft is also 35mm long enabling you to support the end with a bearing in many modern helicopter designs.The OMH-4535-1260 is designed for sport and 3D flying on 6 cell Li-Po batteries and develops a maximum power output of 1998W (3300W for 5 seconds) at around 28,000 rpm.• High Performance• High Efficiency• Great Heat Dissipation