What is the difference between prototype and production molds?

Prototype molds (often Class 103 or 104) are usually made from aluminum or soft steel. They are fantastic for proving out a design or producing a few hundred to a few thousand parts. They are cheaper and faster to build but will wear out sooner.

Production molds (Class 101 or 102) use hardened tool steels and high-quality components. They are an investment designed to run hundreds of thousands or even millions of cycles with very little maintenance. They often include advanced cooling features to minimize part cost by reducing cycle time.