Floor Standing Stainless Steel WC with P trap Product Details Company Name Franke Sissons Ltd. Brand Name Franke Model Number HDTX597 Maximum Flow Rate 4.5 litres Maximum Volume 4.5 litres Category WC Suites Available In United Kingdom Efficiency Rating Chart Company name:Franke Sissons Ltd. Model:HDTX597 4.5 litres 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.