The 2nd battery is really a 650 mAh disposable battery. The pen also comes with two differing types of cartridges. Selina G. Purple Paradox For the last 3 yrs this is the only flavor of juice which i use. I by no means get tired of it and don't https://johnnyjiphy.yomoblog.com/34439928/an-unbiased-view-of-cookies-dual-chamber-disposable-review