I'm looking to replace my stock airfilter with a UNI Filter.... but im confused on the correct size to order.... if anyone can help me out....

UNI High Capacity Two Stage Pod Filter | MotoSport

Or do I need to go with this one in order to fit my ATV??

UNI Two Stage Pod Filter | MotoSport

Are you going to leave the air box on? I used #4119 for inside box its an oem replacement..I cant remember the firstt two numbers tho..but just look for an factory replacement filter an you willbe fine..Maybe NU4119