Optima 49 dual flush push button from Siamp is compatible with the Optima 49 dual flush valve. The front of the button features a simple, elegant design in a beautiful chrome finish. The button features an easy clean design for additional hygiene and is ideal for high traffic areas with its reliable directly connected mechanism which should ensure that this button stands the test of time. This button requires a 38 mm hole without the shroud and an 18 mm hole with the shroud.