Hi moseIlla,
First, glad to have you here on the ECF Forum..
I believe what you are talking about (correct me if I'm wrong, please) is the KR808D-1 Series e-cig ur roommate has.
The one that is on the V4L site (battery) has a male
threads and the one you got (battery) has female
threads..
The (I will call it the 808) 808 has been around a while and has gone thru some changes. The 510 has been around too for a while and also has gone thru some changes (for the better on both).
The are both good e-cigs to start with. One (808) is a 2 piece and the 510 is a 3 piece. By that, I mean, is the 808 has the cartomizer (the atomizer built into the cart. hence the cartomizer or carto.) People find that one very easy to use due to the fast changing of the carto and no real mess with liquids. The 510 you have to refill the cart and can be messy @ times. Also with the 510 some people can drip (take cart off (no filler inside) and drip 2 or 3 drops of liquid directly on the atty).
Both are wonderful to use in MHO. I myself started on the 510 and I got my wife started on the 808.
As for the usage of the 510, specially with the Auto battery is to NOT drip while using the auto batt. there is a hole in the middle if the battery and liquid can easily find its way into it and you will have problems down the road. The manual battery would be the way to go if you want to drip. Also, the auto battery will go off if you blow air into the LED (front) area of it. The auto has a cut off which can be anywhere from 3 up to 10 seconds. (the older ones have the faster cutoff) The manual batts have no or a much longer cutoff (anywhere from 10 to 15 seconds) I myself like the ones with NO cutoff. The reason for the cutoff is so you do not ruin the atomizer.
Hope this helps and if anything else, please ask..