A super-small 40mm EDF. This cute little ducted fan system puts out up to 170g of thrust, great for small indoor or multi-fan projects. Spec. Weight: 28g Kv: 8400rpm/v Size: 42 x 39mm Battery: 2~3S Voltage: 7.5, 8.0, 8.5V Current: 13.0, 15.0, 17.5A Thrust: 130, 150, 170g Watt: 97.5, 120, 148.8W Efficiency(g/W): 1.33, 1.25, 1.14