This is the E-Flite BL400 Ducted Fan Outrunner Motors, 3500kV (Twin Pack)

E-flite now brings you a small lightweight outrunner motor designed specifically for small single and multi engine ducted fan operation.

Features:
Ideal for small ducted fan models from 15- to 25-ounces using 3-cell 2100mAh Li-Po packs
High torque alternative to inrunner brushless motors
Slotted 9-pole Outrunner design
High quality construction with ball bearings and hardened steel shaft
Quiet, lightweight operation – just 2 ounces (56 g)

Overview:
The great performance and small size of the E-flite 400BL ducted fan motor make it a perfect match for single- and multi-ducted fan models. The high RPM per volt (3500Kv) design allows for high RPM capability on most 66mm fan units.

Tech Notes:
You will need...
20A Brushless ESC (2)
66mm 3 bladed Ducted fan unit (2)
11.1Z 2100mAh Li-Po (2)