filter base cap 110 engages the stub shaft 116 to secure the filter base cap 110 thereto the filter base cap 110 may have one or more threads that engage with mating threads of the stub shaft 116 or may merely be press fit or friction fit engaged with stub shaft 116 further in alternative embodiments the filter base 104 may have a threaded cavity configured to mate with external threads of a stub shaft of the filter base cap with primary reference to fig5 7 the filter base cap 110 includes a plurality of interconnected web features 126 the interconnected web features 126 may also be referred to as spoke features the web features 126 and sidewall 128 and annular sidewall 136 generally define an inner cavity that is segmented into a plurality of cavities that include a central cavity 130 a plurality of small side cavities 132 and a plurality of large side cavities 134 cavities 130 132 134 are recessed below a top end 138 of annular sidewall 136 as well as sealing surface 140 of seal element 122 with additional reference to fig3 the central cavity 130 receives the stub shaft 116 of the filter base 104 when the filter base cap 110 is attached to the filter base 104 the web features 126 that bound the central cavity 130 may be threaded so as to mate with any threads of the stub shaft 116 alternatively the web features 126 may be flexible enough to be press fit or friction fit engaged with the.