This is an adapter from the Polaroid Cube mount to a Nerf tactical rail. Works with the waterproof case and other mounts for the Polaroid cube. It fits very snug and secure to most Nerf blasters. Remember the cube has a wide-angle lens. Mount on the farthest back tactical rail. Also if you turn the cube in the mount you can easily mount it on side rails Check out the original for a GoPro mount version http://www.thingiverse.com/thing:629634Print the two parts separately, then super glue them together. Depending on your printer tolerance minor sanding is required.