Check the listing for details. Rubber Stoppers 26mm to 32mm, 4 Pcs 25mm Solid Tapered Lab Rubber Plugs. Condition: New. Listed at 16.69 USD. Description:Solid Silicone Stoppers: Made of silicone rubber, resistant to cracking, shrinking, hardening, or breaking. It has good resistance to chemicals, acid, and alkali resistance, high-temperature resistanceHigh Temperature Resistance: With a heat tolerance of up to 600°F/315°C, these silicone plugs can withstand extreme temperatures without compromising their performanceTapered Design: The tapered shape allows for a secure push-in fit into holes and openings of different sizes.