Back to Wall, 4/2.6 litres dual flush when used with the Appropriate Conceala cistern Product Details Company Name Armitage Shanks Brand Name Sandringham 21 Model Number E8974 Maximum Flow Rate 2.95 l/min Maximum Volume 4/2.6 litres Category WC Suites Available In United Kingdom Efficiency Rating Chart Company name:Armitage Shanks Model:E8974 2.95 l/min The average flushing volume for dual flush WC Suites and Cisterns is calculated as (a + (3 × b)) ÷ 4, where a is the full flush value and b is the low flush value.