BETAFPV 1805 series brushless motors come with 2 different KV value. 1805 2550KV motor is great for 4S power and 1805 1550KV motor is the best for 6S power. Combined with 35A AIO Brushless FC, it will provide you huge output power to build incredible racing drones. 1805 series motors are suitable for 4-5 inch quadcopter, we recommend using 5125/5020 propellers with the motors to get the excellent power effect during your FPV racing.