The Shen Drones Insider 4" Cinelifter Kit is a spinoff of the Shen Drones Dualist with some freshly added details. The original Dualist ducts were about 1mm thick. The new Insider has an increased thickness of 3mm, which made it more durable and less flimsy, while only increasing its weight from 36 to 45g. Now you can take the duct on and off without re-soldering the motor. The original duct had screws threading directly into the 3d print so Shen Drones changed it to the trusted friction-fit-over-standoffs interface. This cinewhoop pops off the ground with barely any throttle, and is whisper quiet! Fits 4" Bullnose props without the hassle of prop cutting.