I would have ordered the extension with my 2.5 if provari would have had it, but they didn't. Then once I received my 2.5, I realized that I really need it, if I am wanting to use my longer batteries with the base. I really wanted the tatroe tanks, and I was going to hold off on ordering them for a few weeks. Then friday I just thought, with my luck if I waited, they would be sold out of the tatroe tanks. So I was already ordering the tanks, just added the rings to the order. The post that had the link to gr modders, just mad me panic, I think that gr, must have some of the older rings, and cig techs must have the newer ones.