Disabled WC Product Details Company Name Franke Sissons Ltd. Brand Name Franke Model Number G21743N Maximum Flow Rate 4.5 l/min Maximum Volume 4.5 litres Category WC Suites Available In United Kingdom Efficiency Rating Chart Company name:Franke Sissons Ltd. Model:G21743N 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.