Made of stainless steel and silicone. Designed to firmly catch the ridges of the bottle on both sides so it can hold up to 13lb internal pressure. Soft tapered silicone fits more snugly in most bottle neck to avoid any air leakage. Coated surface makes a smooth and comfortable edge for easy release even for arthritic hands. Easily seal standard glass bottles of champagne, Prosecco, Cava and other sparkling wine
