Double Kitchen Sink Drain Waste Trap - Main Diameter: 115mm; - Round or rectangular overflow of your choice; - Washing machine / dish washer input. Traps are designed for water to hold back sewer gases. Thanks to its shape, a bottle trap retains a small amount of water in its bottom. This water stock acts as a seal that stops nasty sewer smells. This model has got two kitchen sink baskets to be used in double sinks and is suitable to connect washing machines or dishwashers. It has also got extra overflow which will fit either rectangular or circular sink overflows.