The design is remixed from arod24's thingiverse.com/thing:475349 gear for Phantom 2 (mine is for Phantom 1). I have changed the clamps so that the extender doesn't need help to hold on to the stock gear of Phantom 1 anymore and fits pretty snugly. It will stay on during the "normal" landing and come off only in case of a hard one. The intent is, as with most extenders, to provide extra space for a gimbal (DYS 3-axis AlexMos gimbal in my case).
Attention the remixed thing is ONLY for Phantom 1 stock gear, don't try to print for other makes as you'll waste your time and plastic
This thing should print just fine as shown on the printing table without support or raft with minimum overhangs that don't hurt