97-107mm Inlet x 31/2/90mm Outlet Flexible WC Connector (Long Length) with 1.1/4 Universal Vent Boss. There is no British Standard for Flexible WC Connectors but McAlpine Connectors comply to German Standard DIN 1389:2000-05 for Flexible WC Connectors. Tested by German Testing House LGA, Certificate Number 0120208-02 and other Testing Houses. Tests prove conclusively that there is no build-up of sediment and the product is perfectly fit for purpose