I was gonna say, you could probably spend 50 bucks or even find some scrap wood and metal and replicate that fairly easy. And seeing how your probably not looking to do 300+lb belt squats you could probably attach it to anything.
I've seen ppl use these and just use a belt with a hook around the bar.
Invalid Link Removed
Basically you anchor this to the floor and put the barbell in, on the other end you stackvthe weights and attach the belt