Product Name: Black Silicone Rubber Hole Plug Material: Silicone Rubber Shore Hardness Range: 40-50 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. Actual product may vary in size, color, and printing. The size listed in the specification refers to dimension 'a' in the image, which is the measurement of the main body. The smaller end of the rubber plug is inserted into the hole. When selecting a plug, choose a size slightly larger than the actual hole diameter to ensure proper sealing and prevent dislodging.