When I started doing portable SOTA operating back in 2013 I quickly improvised a portable dipole centre connector, consisting of a plastic Sistema brand food container, 2 screw terminal posts to attach the wires and a hook to attach to the top of the squid pole, to a wire loop embedded in the top section.
Over the years this has served me well, able to attach one or more dipole legs for operating on different bands. However plastic Sistema boxes are not too strong, and I've had to replace the container a few times as rocks and falls out in the field have taken their toll, cracking the case...
After the last bit of damage decided must get something a bit more rugged, and purchased a dipole connector from Tet-Emtron Antennas in Western Australia, http://www.tetemtron.com.au/Dipole-centre-kit-with-insulators-p/te-dck2.htm
Here it is
And the reverse side
Also got a pair of wire winders to replace the fragile wooden ones I made up. A little heavier but more robust.
Need to try it out in the field on my next SOTA/WWFF expedition...