The McAlpine MACTUN-2 is a combined tundish and non-return valve that provides a reliable and efficient solution for protecting against backflow in a range of plumbing applications. Like the MACTUN-1, it is the only combined tundish and non-return valve with a silicone membrane seal, ensuring that it will not be affected by hard water areas. The MACTUN-2 is made from high-quality materials that are resistant to corrosion and can withstand high temperatures. It features a silicone membrane seal that ensures a tight and reliable seal, even in hard water areas. The tundish and non-return valve combination of the MACTUN-2 provides a reliable and efficient solution for protecting against backflow, which can cause damage to plumbing systems and create a risk of contamination. The non-return valve ensures that water flows in only one direction, while the tundish provides a visual indication of any excess water that may be present in the system. Overall, the McAlpine MACTUN-2 is a reliable and efficient solution for protecting against backflow in a range of plumbing applications. Its high-quality materials, silicone membrane seal, and combined tundish and non-return valve design make it a durable and long-lasting choice for both residential and commercial plumbing systems. The MACTUN-2 is similar to the MACTUN-1, but may have different inlet and outlet sizes or other specific features that differentiate it from the MACTUN-1. ・ MACTUN incorporates a self closing membrane which opens to allow discharge to flow freely and then closes to form a seal. This prevents foul odour or sewer gas entering the building when installed into a waste or soil pipe.