So, Gtech are really struggling with getting their Small Power Brush head for the Pro 2 in stock for the millions of people who are desperate for it. In fact I ordered one and it ended up never being in stock in the first place! It should hopefully start coming now though. But whilst everyone's waiting, I have discovered something.
Out of curiosity, I ordered a Gtech MULTI Straight Suction Upholstery tool from Amazon. Even though you'll never find anywhere saying it can be used on the Pro 2, I am hopefully one of the first to confirm you actually can use it on the Pro 2, with or without extension tubes. It fits in nicely, even though you do have to bear with the curved fitting on it, which may be a slight struggle when it comes to fitting it on to an extension tube, but it fits very well anyway.
It feels nice to use, has a good rubbing feel to it, and first impressions, I like it. It does have a pivoting head but shouldn't be a problem since there's a tiny hose that connects to it, like that of an electric powerhead. If you put your hand against the suction port you can really feel air entering it too, especially on Max speed.
Only hours since I started using this tool, but if you want the turbo brush that Gtech are trying hard to get into stock and it never comes, get this as an alternative. Yes, no rotating brushes, but it does work :)