Stainless steel drain barrier suitable for installing within either outlet or inlet of both 100mm clay/cast iron or 110mm PVC drainage pipe. Secured into pipework within drainage chambers, effectively stopping rats and rodents from entering a property via a drainage system. The Rat blocker provides a permanent, simple solution to the problem of rats in sewers. The device prevents rats from moving from the main sewer into the pipes servicing properties. The Rat blocker is now even easier to install. It can be placed in either the upstream or downstream location inside the sewer. Simply insert into the chosen pipe, making sure that the arrow on the device points in the same direction as the flow of waste.