Siamp 32500007 Optima 50 Flushing Mechanism, White

Amazon

WRAS Approved Flush valve pre-fitted in products by Vitra, Twyford, Lecico, Roca and many more Replace an existing Siamp flush valve with ease, without the need to remove the cistern from the wc pan Dual flush Adjustable height & overflow, Manufacturer: SIAMP

Zoro Tools

Optima 50 Dual Flush Valve with 11/2" & 2" Outlet that can be installed into plastic or ceramic cisterns.