The Silca Chain Coupler, which comes complete with a cable, is a replacement part for use with the Ultimate Chain Waxing System, should your original coupler be lost or damaged, or simply if you'd like an additional coupler so that you can have multiple chains drying at the same time.
The coupler should be looped through five or six links, with the spare chain left hanging loose, to make sure the chain is properly spread out and won't stick to itself.
It can then be used to dip the chain into the Wax Melter, agitate it to make sure the wax reaches all surfaces, and remove the waxed chain to dry and cool on the waxing stand, before it is installed on your bike.