Close Coupled WC Suite 6/4litre Dual Flush Product Details Company Name Twyford Bathrooms Brand Name Option Model Number OT1148WH/OT2396WH Maximum Flow Rate 4.5 l/min Maximum Volume 6/4 litres Category WC Suites Available In United Kingdom Efficiency Rating Chart Company name:Twyford Bathrooms Model:OT1148WH/OT2396WH 4.5 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.