These are mounts to hold the TrueRC Bardpole antenna. There are three versions: 

1. Subcutaneous – you'll make an incision in the foam of your plane, and run the feedline under the surface (you can patch the surface with tape).  This is the most aerodynamically sound, and what I would do if it's an option. 
2. Rear exit – the feedline comes out the back of the mount, and goes wherever you need it to
3. Side exit – the feedline comes out the side, as above

To fix the antenna in the mount, slide it between the two halves, with the feedline coming out the bottom, and slip some heat shrink tubing over the halves. To hold more tightly, I'd recommend adding a patch of pressure-sensitive adhesive (e.g. VHB) between the flat side of the antenna and the print. Shrink the tube, and you'll have your bardpole securely fastened in the mount.

I'd recommend gluing the flat side of the print down to your plane's surface, but some sort of pressure-sensitive adhesive (such as VHB) ought to hold it on fairly well, too. 

While I was at it, I've also uploaded my bal-and-socket adapter for bardpoles. This is designed to be used with AirbladeUAV's sockets originally intended for TBS's Immortal-T dipole antenna.