Replacement Self-Flush Assembly for Stainless Steel M1 / MX Series Pumps, 1/4-28 (40 mL).  Self-flush body, inlet and outlet flush check valves, diaphragm, o-ring, and installation instructions. (1 self-flush kit per pump head; 2 kits required for dual-head pumps).

Head Kit Installation Procedure can be viewed here.