When we first started out in DyeSub we were fortunate that a guy in North Wales was selling up his complete range of equipment. I say fortunate because it included an Adkins Beta Major with the matching compressor!
At over £2000 to buy new, we'd never have purchased one. It's a breeze to use even if you have a large run to do. The pneumatic pressure closes the plates and also releases them when the time is up.
John