What size UNI do I need?

[ridehonda400ex]

Im thinking about getting an UNI and on rmatv.com theres all these different sizes, which one do i get?

[CJM]

All you gotta do is plug in your model atv and it will select the right one for ya.

[426kidz]

x2;)

[AtvKid4Eva]

NU-4126ST is the 400ex UNI part number