Extrusion dies can be made to form a virtually limitless array of shapes and sizes. The die itself is a steel disk (normally H13) with an opening, the size and shape of the intended cross-section of the final extruded product, cut through it. Dies are broadly grouped as solid dies, semi hollow & hollow dies. Combination of solid, semi hollow & hollow shapes may be incorporated into a single die. The choice of design and manufacturing methods will depend on the profile, press and container size, and production requirements. The best combination of product performance, quality and cost is achieved when the product designer, the die maker, the extruder, and the purchaser recognize each other's requirements and work together.