The patented door provides access to the thru-hull fitting and seacock inlet beneath APHS hull strainers. There is no need to remove the entire strainer to clear nuisance marine growth. C84400 Bronze body and door#304 Stainless steel filter screen with .077" perforationsEasy field replaceable screenPressure relief holes in door castingNOT TO BE USED IN POTABLE WATER SYSTEMS