The McAlpine ARB-1 Anti-Rodent Barrier
 is a non-return valve for WC connectors that deters rodents and prevents backflow in 4"/110mm drainage pipes. It features a stainless steel mesh-backed plastic door that allows waste to exit but stops rodents from entering the building through the WC. 
Key Features and Specifications
Function: Deters rodents from entering the building through the WC and prevents cross-flow/backflow of water in pipes.
Material: Manufactured from black polypropylene to prevent light penetration (which can attract pests) and features a stainless steel mesh-backed plastic door that rodents cannot bite through.
Compatibility: Designed for use with any McAlpine rigid or flexible WC connector that has a 4" / 110mm rubber outlet seal.
Installation: Can be installed in both horizontal and vertical positions. The existing rubber seal is removed, and the ARB-1 unit is push-fitted into its place.
Compliance: Suitable for use where special measures for rodent control are necessary, as recommended in Approved Document H1 of The Building Regulations 2000 (2002 Edition).