Yes, you need a 510 to 901 adapter. I have one (not from Provape) and fits on the ProVari and KR-808D1 carts. The one ProVape sells looks the same and they state on the ProVape site: "also compatible as a 510 - kr808d1". But, maybe you have a KR-808 cart not type KR-808d1? If so, I do not know if it fits in this case.