Functions: (1) Insect prevention (2) Anti-odor, deodorant (3) Anti-backflow Features: (1) Easy to install, plug and play (2) Fast drainage (3) Adjustable size (4) Automatic opening during drainage, self-closing after drainage Working Principle: (1) When water flows into the floor drain, the water's weight opens the ABS seal at the bottom, allowing water to drain smoothly. (2) Once water flow stops, the ABS seal automatically closes due to gravity, creating a complete seal that prevents sewer gases, pests, and overflow from rising up. Material: ABS, Metal Applications: Fits holes from 3.3 to 4.5 cm in diameter Specifications: - Easy to install, plug and play - Fast drainage - Adjustable size - Automatic opening during drainage, self-closing after drainage Package Included: 1 x Floor drain core 1 x Fixing reduction ring Notes: 1. Slight measurement differences may occur due to manual measurement. 2. The actual color of the item may vary slightly from the images shown, due to monitor display settings and lighting conditions during photography. Thank you for your understanding!