Injection molding machine molds can be fastened in either a horizontal or vertical position. Most ma-chines are horizontally oriented, but vertical machines are used in some niche applications such as in-sert molding, allowing the machine to take advantage of gravity. Some vertical machines also do not require the mold to be fastened. There are many ways to fasten the tools to the platens, the most com-mon are manual clamps (both halves are bolted to the platens); however, hydraulic clamps (chocks are used to hold the tool in place) and magnetic clamps are also used. The magnetic and hydraulic clamps are used where fast tool changes are required.