I bought this software quite a long ago from Codecanyon when I was into cracking and it works like a charm. There are free softwares out there that are as good as this one but DOMsocks's GUI is quite nice and easy to use. I had money to waste so I bought it, don't complain about it because I'm sharing it for free
It has some nice features and It can also check if the proxies have been banned from Paypal, I've never used this function so I don't know if it works or if it ever worked at all. Apparently the source code is protected and there's no license system.