The two diaphragms are doing the work to prime and push the liquid through the pump system. Tapflo diaphragms are of sandwich compound construction, superior for continuous heavy duty service.
The solution with an integrated metal core, provides a completely smooth surface in contact with the liquid, without any nuts or washers. This results in no leak through and a diaphragm which is easy to keep clean.
The diaphragm is available in PTFE (food grade), EPDM, white EPDM (food grade), NBR and FKM (FKM on certain models only).