Filters that remove particulate and other solids from fluids often come in various sizes and include various types of seals. However, filter bases to which the filters are attached are generally manufactured to accommodate only one specific size of filter including one type of seal. A filter base of the present invention includes a filter attachment portion and a sealing portion. In order to expand the different sizes of filters that the filter base can accommodate, the sealing portion includes a first annular sealing surface with a relatively small diameter and a second annular sealing surface with a relatively large diameter. The two sealing surfaces can be any combination of radial and a face sealing surfaces. The filter base is used for filtering fluids, such as fuel, in an internal combustion engine.