SIAMP 32335510 33A Storm Flush Valve - White 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. Single flush, height adjustable, and with an adjustable overflow. Manufacturer: Siamp. Features & Benefits: Will fit into an existing Siamp Bayonet. Can be installed into plastic or ceramic cisterns. Single flush, full cistern discharge. Height Adjustable. Actuation effort below 20 Newton. For lid holes ranging from 18 to 50mm, with or without collar depending on diameter. Adjustable stirrup that fixes the cistern lid and enables a non-alignment position. Adjustable overflow can be cut in increments of 5mm. High flush rate of 3.5l/s. Foam pan seal supplied for compensating pan irregularity.