OBS provides high-end E-cigarettes and mainly deal with the R&D, sales and production of e-cigarettes. Simplify your vaping experience without sacrificing power when you use the OBS KFB. This OBS KFB is an excellent pen starter kit for those interested in sub ohming, thanks to its built-in sub ohm atomizer tank that allows for greater clouds. The side fill design makes refilling simple while also helping to prevent leaks and spills. The tank can hold up to two milliliters at a time to help spread out refill times and operates on a single 18650 lithium ion battery.