The KR808D-
1 is pretty much the standard among ECF members and is what we and suppliers mean by such abbreviations as Kr8, 808, and KR808. The D-2 is
LeCig's designation for the E9 model, mass marketed (on the Internet and in malls) as Smoke51 DUO, Green Smoke*, and Vapure. They are
not compatible, i.e., you can
not use a D-2 carto on a D-1 battery or vice versa (although LeCig does sell
adapters).
* Not to be confused with Green
Cig, which is yet another model sold by LeCig and by NHaler. GreenCig
is compatible with the KR808D-1 ... at least somewhat: GreenCig cartos won't work on
manual Kr8
batteries (unless you use an adapter sold by
NHaler).
The only one of these
three models I recommend is the Kr8 (also sold under the brand names of MaxX Fusion, VOLT, Vapor King, Easy, and Nebula). The two best implementations IMO are the expensive
Bloog MaxX Fusion and less expensive
Smokeless Image VOLT.
For more information about these models and where to buy them, check out this page of my
WWV Version 2.