Haywood Jakissme (sir or Ms.?) the kr808d-1 and d-2 are very different in some aspects and similar in others. Both are male connections, both run at 4.2v hot off the charger (gen 1 kr808's, not gen 2 which runs at 3.6v regulated), both are 2 piece by nature (as in carto and batt, not cart, atty, and batt, though on 808d-1 you can use 901 atty's). The e9 though (other name for d-2) doesn't last as long, doesn't charge as fast, has less carto options, and is used by a number of companies that heavily mark it up (as in as much as $50 a batt). Hope this helps...