Abstract: A fluid dual filter having a primary fine mesh filter element, a secondary coarser mesh element in parallel with the main or primary element and a plurality of bypass valves which are normally closed to block flow through the secondary filter element but which open at an elevated fluid pressure caused by blockage of the main filter element thereby allowing flow through the secondary filter element. The valves are located downstream of the secondary filter element in order to prevent their contamination by any foreign matter in the fluid to be passed through the filter.