The Bailey Drain Test Plug with Plastic Cap in 100mm (4 in) size is perfectly suited for testing standard domestic and light commercial drainage systems. This mid-range size is ideal for typical residential waste pipes and drainage runs, offering versatility across a wide range of common applications. The centre locking mechanism ensures the plug remains securely positioned during air or water testing procedures, whilst the steel plates provide the structural integrity needed to withstand testing pressures. Brass wing nuts allow for easy hand-tightening without the need for additional tools, and the plastic blanking cap creates a reliable seal to maintain consistent pressure readings throughout the testing process. Features and Benefits:100mm (4 in) diameter suits standard domestic drainage systemsCentre locking design prevents movement during testingSteel plate construction withstands testing pressuresBrass wing nuts enable tool-free tighteningPlastic cap ensures effect