The Kandy Pens 350MAh Batteryis a battery pen-style rather than conceal type, which has part of the advantages and disadvantages. The biggest advantage is that it can save any sized cartridges so you don't have to worry about whether a trolley will fit as you do with most of the Rokin battery like Rokin Viper. The other pros are that using 350 with cartridges feels more natural because of the combined length of the battery and the cartridge feels very comfortable to hold.

Portability is the main loss site located, in particular, portability with attached cartridges. The length that makes 350 feel comfortable also makes it very awkward to enter into a pocket with a cartridge that is connected to it.