PRACTICAL FUNCTIONS - The floor drain filter with the automatic closing design, effectively block the bugs, bacteria; Seal stinky smell and odor from sewage gas; Prevent the drain water from backing up to the room; Anti- water leakage and overflow. UNIQUE DESIGN - The floor drain is designed in V-cup shape, which ensures smooth draining and quicker water flowrate. Unique S-shape automatic closing design can strongly prevent backflow, the stinky smell and odor from sewage pipe, and block bugs and bacteria. APPLICATION RANGE - This item can be used with floor drain of the shower room and basement,effectively block backflow, odor and bugs in the sewer. Environmentally Friendly -totally environmental-friendly material; No smell and no toxic; Safeguard for your family health; No worry about deformation after stretching, super flexible; Ever-lasting and durable; Strong anticorrosion effect. Installation guide: 1. Please measure precisely the internal diameter of the drain mouth, in case any inconvenience brought by unmatched size 2. Measure the depth of the tube 3. Install the floor drain one way valve 4. Because the stickiness and softness feature of silicone, make support apart the mouth of drain grate with your hands in the first installation for the smooth draining colour:blue Material:Silica gel size:9.5*5cm,6*5cm Port diameter 5.5cm Package Contents: 4* Silicone Drain Backflow Preventer 4* Stainless Steel Strainer 4* Stainless Steel Retaining Ring Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.