+ 1 for Valley View Vapes. He used to make the Texas tanks for Vape Dudes, then they took his design and started making their own. Ray is a nice guy and very active on his supplier threads. The only trouble is he's a one-man operation and when he takes a much needed break (not surprising since so many people recommend his products), the whole shop shuts down.
I use one of his 5ml Economy Polypro tanks more than any of my others (it somehow got dedicated to my fav juice), mostly because the side screw is so easy. It's also very durable. I could throw it on cement, and unless it hit just at an angle to knock the screw off (you can buy replacements) it would probably only bounce - well, maybe a scratch is it was cement.