E-cig Overview 

As a general rule these days, everything is made in China!  E-cigs are no different.  As a result, there is a good deal of conformity in the design of e-cigs.  Most e-cigs are designated 'OEM' (Original Equipment Manufacturer) which, paradoxically, means that anyone can use that design and just brand it up as their own - one reason why 'OEM' is known coloquially as 'Owned by Every Moron'.  

Several defining criteria can be used to distinguish e-cigs from one another, but perhaps the easiest is by battery size - there are two main kinds: 510 size, and 808.  There is no real difference, except that 808's have slightly bigger-diameter threads - that's it really.  So, for example, a ROKstar large e-cig, which uses a tank, and e-liquid, has a 510 battery, so it can use 510 cartomisers in exactly the same way as a standard 510 or a 510-t (the 't' stands for 'tank').  So, whether you are looking at a big e-cig or a small one, one with a manual battery or one with an automatic battery, one that uses cartomisers or one that uses cartiridges with a seperate atomiser, you will almost always be using a 510 or 808 battery.

So, what's the difference between a 510 and an 808?  An 808 is a male battery, requiring a female tank/atomiser/cartomiser.  A 510 battery is 'female' and needs a male tank/atomiser/cartomiser.  That's it.  Both, in our experience, are good batteries that give pretty similar performance.