Close Coupled, 4.5litres single flush with delayed action fill valve Product Details Company Name Armitage Shanks Brand Name Contour 21 Model Number S3054, S3654 Maximum Flow Rate 4.5 litres Maximum Volume 4.5 litres Category WC Suites Available In United Kingdom Efficiency Rating Chart Company name:Armitage Shanks Model:S3054, S3654 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.