The top picture is a set of BMC filters. Contact
Factory-Pro for those. If you don't have a jet kit, you'll need one for any pod filter setup - and Factory-Pro can hook you up there, too. They used to list the B4 pod kit on their site, but I don't see it there anymore, but they ought to be able to hook you up.
Looks like the silver framed bobbed B4 is sporting K&N individual pods. They're a little smaller than the BMC's
The B12 is wearing 2 K&N pods, each one mates to a pair of carbs.
As for the size, I don't know. If no one comes up with the answer, you can always measure the mouth of the carb yourself.