Ok so I purchased an e-cig that says "ecigaratte" on the atty. From what i have seen on this site it looks like the M series. 401 I think. I see the only physical difference between 401 and 402 batteries is the length. Do they run off the same atty? How can i tell the difference between the 401 atty and the 402? I need to know so I can buy a PCC for it.