what air filter for 2006 C50 boulevard

what are the differences in k9 or k8,8,8,6 air filters???

i was looking at oem parts for my c50 boulevard and it has both, im confused. [ATTACH=CONFIG]33600[/ATTACH]
here's what i have, can anyone help?

thanks in advance....bless

Part #13780-42F20 element is the one you are looking for. The K9 model has a distinctively different looking air box and cover.

thanks lee. yesterday i went to the suzuki dealer and he had told me that the difference in K's had to do with the year...then i had to show him the pic i posted and he found it for me. however, i'm ordering it on line...thanks for help.