MIFAB's M-500 Series of pressure drop activated trap seal primers deliver water when line pressure changes as little as 3 psi. This is a key benefit given today's fixtures that use less water with a lower pressure drop. An accessible filter screen provides easy access for cleaning. The product can be taken apart and cleaned without affecting performance. Cartridges can be interchanged to provide different amounts of water delivery. MIFAB. Circle 13.