Made of nylon and fiberglass, Autel Robotics' low noise propellers for EVO II are durable and shatter resistant in extreme crashes. When operating normally, the willow-shaped design helps reduce drag, maximizes flight efficiency, and most importantly reduces propeller noise. Each propeller is collapsible, making it easy to store inside a drone case or gear bag. Please note that this pair of propellers should not be mixed with standard propellers. The combination can cause unstable flight.