The three types of oil filters used by 356's and 912's are Mann, Fram and H-filters. The early 356's and some of the early A's use the Mann filter, which is identified by a 10mm bolt. The Mann filters also use two different decals depending on how early the car is. Porsche did not designate when they stopped using the early decal, so compare with the original decal for accuracy. The majority of 356's and 912's use either a Fram filter, which is identified with a 12mm bolt or an H-filter, which identifies with a 16mm bolt. There are no engine numbers or chassis numbers that identify the correct filter, so the best way to tell is to measure the bolt. It is also helpful to note that H-filters canisters are usually all silver or silver with a black cover, while Fram canisters are orange with a black cover