Specifications: Voltage: 1 - 2 s Test Data of 1811-2000KV: No-load Current: 0.4A / 7.4V Max Power: 38 W Voltage: 2S, Prop: 7*3.5, Current: 4.1A, , Thrust: 165g Voltage: 2S, Prop: 6*3, Current: 3.4A, , Thrust: 150g Voltage: 2S, Prop: 5*4.5, Current: 4.0A, , Thrust: 135g Test Data of 1811-3800KV: No-load Current: 0.6A / 7.4V Max Power: 59 W Voltage: 1S, Prop: 7*3.5, Current: 5.0A, , Thrust: 110g Voltage: 2S, Prop: 5*3, Current: 7.5A, , Thrust: 205g Voltage: 2S, Prop: 4*3, Current: 6.0A, , Thrust: 170g Test Data of 1811-3900KV(No load current: 0.8A / 7.4V): Voltage: 2s, ESC: 7A, paddle: 4 inch, current: 4.5A, thrust: 127g Colour:Silver Material:metal Size:5x3.6x1.5cm<br><br>Package Contents: 1* RC 10 Grams Micro-type Brushless Motor kit Only the above package content, other products are not included. Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.