I have the kit in the picture below and I'm thinking ahead about where to buy my batteries when they need replaced. The manufacturer wants $34.95 for a new battery but I'm thinking I can get them much cheaper than that. The manufacturer (TECECIG) doesn't seem to want to disclose any specifications that would help me determine a possible alternative replacement battery. The only information I could find about these batteries is that they are 2.6 volts. When it's time for me to replace a battery, how can I determine which brand/type of batteries, if any, are compatible with the cartomizers and chargers that I already have? Thanks.