Look at our "Wrestling Season Special" in the Exercise of the Month section for an example of how to use these collars.
This is a collar that slips onto your grappler's Olympic bar, before the weights are placed onto the bar, that allows any kind of handle to be attached via a carabiner. Two types are offered, a short version with 12 inches of chain, and a long version with 24 inches of chain. The best choice depends on what exercise you will be doing, but you can hook a carabiner onto any of the links in the chain, effectively providing a variety of chain lengths. The excess chain will simply hang unused, so when in doubt, go with the long version (however, too much extra chain dangling around during your exercise can become annoying - so if you won't need it all, get the short version).
These collars will allow you to use your grappler base for many exercises that are normally done with a low-mounted cable machine. Use your imagination to perform dozens of exercises (cable-like curls, reverse curls, upright rowing, rowing, front raises, standing tricep extensions, etc.), depending on the type of handle you clip onto the chain.