The Hubsan Q4 is an amazing piece of kit & now you can prolong the life of your quadcopter with this set of 4 spare rotor blades. This pack comes with 2x A blades & 2x B blades. It is important that you put the blades on the quadcopter correctlyl. The Q4 has letts on the wings that corrspond to letters on the blades. Also the red blades must always be at the back of the Q4. See diagram below for reference.