..I'm also curious, maybe a dumb question, but I know the 510 is a standardized threading/size, what is 306? Is it a different standardized size or does it mean something else?
That's not a dumb question and it has an interesting answer. People refer to devices as having "510 threading," which suggests it is a thread size, but it isn't. If you went to a hardware store and tried to find a screw with 510 threading, you would leave empty handed.
In the beginning, manufacturers of e-cigarettes used many different styles of connectors.
One of the first e-cig kits Joyetech came out with was called the 510. I don't know why it was called the 510, but I imagine I will someday; I'm just like that.
Out of the field, Joyetech's 510 connector became the front-runner. I could be wrong, but my guess is because Joyetech introduced the eGo with the same internal threading which took the market by storm. The atty in the device was good, people were already using it for direct dripping, so that became the focus of its use, while the battery moved into the background and the cartridge all but disappeared. So when someone says a device has 510 threading, what they are really saying is the device
has threading like the battery and atty in a Joyetech 510 kit.
The same is true with the 306, it's not a thread size either. The 306 was a Joyetech cig-a-like kit that had the same connection as their 510 kit, but the atty was shaped differently. It was shorter and missing the outside "jacket," but had the same configuration of a steel mesh bridge over a coil, wick and reservoir cup.
The 306 atty had a lower resistance than the 510 attys of the time, which resulted in it providing a warmer vape. Keep in mind that variable voltage devices weren't commercially available yet, so the only way to change the output (watts) was to change the resistance of the atty. The 306 atty became very popular while the rest of the kit for the most part went by the wayside. So when someone says it's a 306 atty, what they are really saying is
it's the type of atty that used to come in a Joyetech 306 cig-a-like kit. You can still buy Joyetech 306 kits today.
Joye 306 electronic cigarette starter kit
There will be a test on Friday.