The Hacker A30 series motors are designed for Larger Parkflyers, 3D Aerobatic, and Scale models from 24oz to 60oz and utliize 2 to 4 series LiPoly batteries. The 14 pole "outrunner" type design creates MASSIVE TORQUE, therefore larger direct drive props can be used without the need for a gearbox. These motors feature oversized bearings, curved neo-magnets, and high-efficiency stator design. The A30 motors produce the most power at lower current consumption than other popular Outrunner designs. We recommend the Hacker X-Series Brushless Controllers for use with the A30 Series Motors A30-L- for 30 to 45 oz. 3D-Aerobatic and Scale models with 2-3 cell LiPoly batteries