A blanking head is an element used to seal the ends of a container, isolating its internal and external media, also known as an end cover. The blanking heads for cylindrical containers are typically rotatable shells. They can be classified by the shape of their surface into convex, conical, flat, and composite shapes. A convex blanking head refers to one with an outwardly convex surface, such as hemispherical, elliptical, dish-shaped, and seamless spherical blanking heads. Some gas cylinders use a composite bottom blanking head with an inward-facing convex surface, which ensures both strength and meets safety requirements for use.