Replacement diaphragm designed for Sloan® Optima Plus™ flush valves RESS-C-1.6, RESS-C-3.5, and RESS-C-4.5. This component includes a white regulator suitable for 3.5 and 4.5 gallons per flush (GPF) systems, ensuring optimal performance and efficiency. Ideal for maintaining the functionality of your flush valve, this diaphragm is essential for reliable toilet operation.