The McAlpine BSW-BR-CP 1½" Basket Strainer Waste is a plumbing accessory designed for use in sinks and basins. Here is a breakdown of the different parts of this model: 113mm Chrome Plated Brass Flange: This refers to the part of the strainer waste that sits on top of the sink or basin. The flange is made of brass, which is a durable and corrosion-resistant material, and it has a chrome-plated finish that gives it a sleek and modern look. The flange has a diameter of 113mm, which is the standard size for most sinks and basins. Spring-Loaded Plug: This is the part of the strainer waste that sits inside the sink or basin and prevents water from draining out. The plug is spring-loaded, which means that it can be easily opened and closed with just a push or pull. This is a convenient feature that allows you to control the flow of water in your sink or basin. Backnut: The backnut is a threaded nut that screws onto the bottom of the flange to secure the strainer waste in place. It is an important part of the strainer waste that ensures a tight and secure fit. Overall, the McAlpine BSW-BR-CP 1½" Basket Strainer Waste is a high-quality plumbing accessory that is designed to last. Its chrome-plated brass flange, spring-loaded plug, and backnut are all designed to work together to provide a reliable and efficient way to keep your sink or basin draining properly. ・ 1½" BSP ・ 113mml flange ・ Spring Loaded Plug ・ Supplied with 41mm fixing ferrule ・ Longer fixing ferrules available as follows: 70mm long Code: BRBOLT70 and 90mm long Code: BRBOLT91