I bought the wife a KR808D1 and tried one of her pre-filled cartos on my Riva 901, I guess it's ok to use w/o an adaptor. It's better than what I'm doing with my cartos I'm filling. Good TH(for me), I like the flavor and the vapor is better. Think I'll start using some of her cartos till I get a bottom feeder. Any reason I shouldn't? Thanks.