MBDoc mentioned what Duke presented in a post a few years ago.

Bosch makes all kinds of parts. Grade A, B; C.

Autozone and others sell the Grade C.

The 72xxx number Duke pointed out is a for real 103 filter, but you may have to look for it if buying locally. Parts shops that specialize in european parts would be a good place to start if you're not interested in buying off the WEB and if you do, be sure it has the number Duke pointed out.