Product Name: Black Silicone Rubber Hole Plug Material: Silicone Rubber Shore Hardness Range: 40-50 Temperature Resistance: -40°C to +250°C Function: Waterproof and Sealed Specification 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, test tube plugs. Note: Images are for reference only. Actual product size, color, and specifications may vary. The size listed in the specification refers to dimension 'a' in the image, which is the diameter of the small end of the plug. The small end is inserted into the hole. For best sealing performance and secure fit, select a plug size slightly larger than the actual hole diameter.