DJI Phantom 2 Vision 9-Inch Self-Tightening Propeller Set -OEM in original DJI packing Self-tightening design optimized for Phantom 2 and Phantom 2 Vision New propeller design allows for more efficient airflow and longer flight times vs. props on the first-generation Phantom Each pack contains two (2) propellers, one for clockwise (CW) rotating motors and one for counter-clockwise (CCW) rotating motors If all four propellers on a quad copter need replacing, purchase two packs of two propellers Thread nuts are integrated into the prop, so these screw on easily with no thread nuts to keep track of