The trick is - some large battery 901/808 threaded
devices have a slot cut across the battery post to get air get into the carto and some do not and are made as if they expect DSE901 cartos to be used (and those actually have a hole in the side of their tube to let air in, just like DSE901 attys). So if you get a fat battery 901/808 that does not have the slot, it is more likely you will need an adapter to let air get into your KR8 cartos. However, if your cartos have a good clear slot cut across their center post, they may get air OK on either.
The other gotcha - KR808D-1 is a true 3.7v devices. many of the fat battery models are lower voltage and will not get the same heat out of your cartos.