good question man. I was wondering the same thing. My vision ultra goes up to 2.5 for lipo and my mk11 up to 2.0. I guess I haven't needed to go higher yet. I am currently working on making one of my mugen mbx5's brushless and one of my mbx5 truggies brushless too. I will need some of those packs soon and a way to charge them. I will have to do some research. I can't wait to have one of these rockets operational[8D]