I got my passthroughs from vaporguys who delivered in two days. They do have the 901 but I don't know what kind it is. I'm having the same trouble you're having with my 801. I don't find the 801s to be compatible.
Okay that's where I had the problem with the passthrough. I bought it from them and I put my 4075 atty on it and it would light up but would not vape so that is what I'm concerned about. All my attys are 4075's