This is the .25 Brushless Electric Motor from O.S. Motors. FEATURES: For .20 - .25 size airplanes Stainless steel prop shaft Rigid rear mounting design Centrifugal fan design with angled ventilation holes draws air through the motor and across the windings and magnets for improved cooling INCLUDES: .25 Brushless Electric Motor with Backplate, four Phillips Head Mounting Screws, 3mm Gold Plated Male Plugs attached to leads, three 3mm Female Plugs with Shrink Wrap, Prop Adapter and Instruction Sheet REQUIRES: 60A brushless ESC SPECS: Rated Power: 440W Rated Voltage: 11.1 - 14.8V Rated Current: 30 - 40A Maximum Current (10 sec): 75A No Load Current: 1.9A Phase Resistance: 21.4 miliohms Maximum Efficiency: 85% kV: 1200 Poles: 14 Shaft Diameter: 0.20" (5mm) Shaft Length: 0.45" (11.5mm) Weight: 5.46oz (155g) Lead Wire Length: 3.5" (90mm) Length of Motor Can: 1.7" (43.3mm) Diameter of Motor Can: 1.47" (37.5mm) Length/rear of Motor Can to Prop Washer: 2.3" (58mm) Prop Washer Diameter: 0.87" (22mm) Thickness of Motor Mount: 0.12" (3mm) Width of Motor Mount: 1.96" (50mm) Height of Motor Mount: 1.96" (50mm) Performance for this motor with different props and LiPo cells is as follows (all data with 60A ESC): Prop Size Max Electric Current LiPo Cells 9.5 x 7.5 34A 3S 9.5 x 8 35A 3S 9 x 6 48A 4S 10 x 6 37A 3S 10 x 7 42A 3S 11 x 7 50A 3S 12 x 6E 48A 3S COMMENTS: Nomenclature is defined as follows: 0MA means 0.S. airplane motor First two digits are the rotor diameter Second two digits are the length of the magnets Last digits indicate the kV of the motor jxs 05/11/11 ir/jxs