If not, let us explain the 2 Most poplar models out there.
3 Piece E Cigarette (old) VS.2 Piece E Cigarette (new)
First We Will Explain The 3 Piece E Cigarette, also the Oldest technology in the e cigarette industry.

The 3 Piece E Cigarette Consist of:
1) A Battery
2) A Atomizer
3) The Cartridge
To use the 3 piece system you must fully charge your batter, twist on a separate atomizer and then lastly slip a plastic cartridge on top of the atomizer and puncture the liquid pack inside.
3 Piece PROS: TYPICALLY VERY CHEAP!
3 Piece CONS: TYPICALLY VERY CHEAP,Short Life Span, Produce Minimal Vapor, Constant Cleaning of Atomizer..Just Not A Good Idea.
The MOST problematic component of the 3 Piece E Cigarette is the ATOMIZER. They Burn Out Very Quickly or Simply Fail to work. One must constantly be replacing their atomizer to enjoy their e cigarette.
PLEASE NOTE: ZEROCIG Does NOT Sell 3 Piece E Cigarettes
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Now Lets Explain The 2 Piece E Cigarette!
The Newest E Cigarette Technology and The Only Thing We SELL!

The 2 Piece Electronic Cigarette Consist Of 2 Simple Components:
1) A Battery
2) A Cartomizer
( A cartomizer is a high quality cartridge with its own built in atomizing device)
What does this mean? It means with every new cartridge / cartomizer you get a brand new atomizer built in. When your cartridge is done, simply throw it a way and screw on a new cartridge.
2 Piece E Cigarette PROS:Produces Great Vapor, Ease of use, No Maintenance, Built in atomizer with ever cartridge, MUCH longer lasting, Newest Technology,
2 Piece E Cigarette CONS:None to report!