I had ego twists and was happy with them, however, the numbers are hard to read. You asked about tanks and such. You can use ego or 510 connections. When I started, I was told 510 was a very important number to remember. It took me a lil while to totally understand why. Lol. Anyways, the difference is that on the ego fittings the metal extends and covers the threading on the ego batteries and 510 doesn't have that metal that covers the thread, looks not totally finished. To fix this problem they make ego beauty rings, also called sleeves or cones, they screw down and cover up the treading on the ego batteries.