This is a set of 10×45 plastic propellers that are ideal for most multicopters. In particular, these propellers are used for Arducopter and the Arducopter 3DR frames. These sets includes one counter clockwise and one clockwise propeller.
The coloured propellers can be used to help you easily see the orientation of your multi copter/ arducopter; use different coloured propellers at the front of your flying platform to easily distinguish between the front and the rear.
You have a choice of colours including green, blue, red, orange, yellow, white and black.