Product Name: Black Silicone Rubber Hole Plug Material: Silicone Rubber Shore Hardness Range: 4050 Temperature Resistance: -40C to +250C Function: Waterproof and Sealed Size: 2.5mm x 30mm Color: Black Shape: T Type Packing Quantity: 50 pcs Features: Corrosion resistance, acid and alkali resistance, high temperature resistance, anti-ultraviolet, anti-aging, long service life, high and low temperature resistance Application: Suitable for various PVC pipes, steel pipes, equipment dustproofing, sewer pipe blocking, sealing aluminum plate holes. Can be used as spray plugs or test tube plugs. Note: Images are for reference only. Size, color, and appearance may vary slightly. The listed size corresponds to dimension 'a' in the imagethe diameter of the narrow end of the plug. The smaller end is inserted into the hole. For best sealing performance and to prevent dislodging, select a plug size slightly larger than the actual hole diameter.