I suppose this is one for Ben :)

I'm extremely curious about these, but I've heard very little about them. Even searching on the Internet there isn't an awful lot of information -but typing Vac Rac into Google will get you lots of information about the Vac Rac affordable rod and reel transportation system, whatever that is.

I've been reading about the types of compressors that some of the top mixers use, and read about Inward Connections Vac Rac limiters (apparently one of Tom Lord-Alge's fave compressors). However, an online search yielded scant information regarding whether they're still manufactured, details of the unit itself or even any distributors or dealers who have them.