The IMR18650 35A from eFest is probably their most well rounded 18650 battery because it has a very high amperage output (up to 35 Amps) while also retaining a high milliamphour (mah) capacity of 2500mah. The purple series is considered the high end from eFest, the brand synonymous with being a trusted supplier to the vape industry. This battery also includes a scratch off anti-counterfeit label so you can rest assured that you are getting genuine quality (be cautious of knock off's online from less reputable online stores - you get what you pay for!).