Apparently not. Here’s another thread about it: Post-T-Vac. It’s designed for men with ED and involves pumping up from a flaccid state and then sliding a very tight elastic ring over the base of the shaft.
Have you looked at the web site and the PRICE? ($550)
You’d do better at a local sex shop or order a “regular” tube and pump online. Going into the tube erect has been considered the “better” way in my experience and from what I’ve read. If your ED is so bad that you cannot get erect at all, there are probably better ways of going about getting erect than this expensive device.