Functions: (1) Insect prevention (2) Anti odor, deodorant (3) Anti defection Features: (1) Easy to install, plug and play. (2) Fast drainage. (3) Adjustable Size. (4) Automatic opening when draining, closing after draining. Working Principle (1)When the water into the ground drain, the gravity of the water will open the bottom of the ABS gasket, dripping unimpeded. (2) After disruption of water, ASB gasket is automatically closed due to gravity.Completely sealed so that the gas in the pipeline, pests and over flow can not be up. Materical : ABS Metal Applications : for 3.3~4.5 cm holes Specifications: Easy to install, plug and play. Fast drainage. Adjustable Size. Automatic opening when draining, closing after draining. Package Included: 1* floor drain core 1* fixed reduction ring Notes: 1. Measurement of the item lying on the table may cause slight difference. 2. The real color of the item may be slightly different from the pictures shown on website caused by many factors such as brightness of your monitor and light brightness when photo taking. Thank you for your understanding