Filters for Optimax 200

How many filters are there and what is recommended maintenance interval? Also best place to buy? I really need to get a manual. Only filter I had on Black Max was gas that I added myself. Black Max was easy to work on. Optimax is totally new to me.

Depends serial # early models had 3 and newer models have 3 or 4 give me your serial # and I can tell you for sure.....OPTI