I know this is a late reply, but thought I would weigh in. The White Cloud Cirrus 3 is its own animal. It doesn't play well with other cartos, and other carts don't work on its batteries. Having said that, I got a kit of three (with their squid recharger which I wish every company would do). This is the smallest ecig battery. Smaller than even the short batteries from V2, Bull Smoke, Titan, etc. However, it last significantly longer than the larger small batteries from other companies. Vape quality is good, and I've been using the same 10 pack of original clear draw carts, and the liquid I'm using draws even better than theirs. Plus, the cart is soft and has windows to check liquid level. It is my go-to for work and those times out when I want to be discreet and stealth vape. The silver battery with black tip has no lights, so it is perfect.
Be warned.. while I can't check, I suspect the batteries operate at lower voltage and the carts are lower ohm, which gives them the better battery life. You cannot charge their batteries on other 808 chargers, and you can't charge other 808 batteries on their 3 connection squid. That said, I'm very happy with these. They are the smallest you can find, plus they have good battery life. Certainly worth the investment - but please know they are not interchangeable with other 808D1 batteries and carts.
Their liquids are so-so, but you can get them in high 36 and 54mg nic levels. On refill they work well. I use high nic juice in these because they are for my stolen moment vapes, not for regular use. Hope someone finds this helpful.