The present disclosure pertains to a fluid filter having integral attachment means which may take the form of a threaded portion of a filter cartridge. The threaded portion threadably interacts with a complementary threaded portion of a filter mounting to retain the filter cartridge to the filter mounting. The disclosure also pertains to a fluid filter having a cartridge made from two plastic shells welded together. The disclosure also pertains to a fluid filter with filter media positioned within a filter cartridge by an end cap with extending ribs welded to one of the two shells which compose the filter cartridge.