well first off you probably have a 9 or i think its 12 also, but 9 is more common. and online, its tough to find them, but the bowls exist, the ashcatchers do also, but they are harder to find, but if you search 9mm and ashcatcher you should find some, ashcatcher is the correct term.

and if you wanna be specific as to what size you have, i believe the measurement is taken from the bottom of the bowl piece, aka the whole where the smoke flows out of on the bowl itself, i believe that is what the standard is.