They look a bit like the ones in the Ferraci kit.
Casting my mind back to when I was last looking at this... This is a wee bit of vague recollection mind. With the 4 inch round K&Ns, I think it's something demented like 210 Mikunis

But with those, the air jet is restrictive, and needs to be drilled out for good results. Marc Whotsisname at Factory Pro reckons that with constant throttle, the jetting's identical to unfiltered.
The K&N stage 2 kit comes with 180s and 190s, I think, for use with the older K&N pods.