Ratwall has a feature of an external hinge and curved flap so there is no restriction of flow within the pipe. It is easily fitted by mechanical compression of the side walls allowing the unit to 'friction fit' from ground level (with additional extension pole) or by hand in a shallow chamber. The flap can be re configured to fit within any inlet of a chamber and no silicone or securing cable are required for installation. The stainless steel ratwall fits securely within 110mm PVC or 100mm clay drainage chamber outlets and will prevent rodents and rats from entering a property