In the year 1962, the Heel-toe weighting type of ping golf club was granted patent. This design was the one that revolutionalized other modern designs and golf clubs that are manufactured in the market today. In the year 1969, another type of ping golf club was introduced which was the perimeter-weighted, investment-cast iron. The reason for this type of ping golf club is that the perimeter weighting is able to increase the moment of inertia thus when a ball is not struck squarely on the face it makes the club more forgiving. Another innovative movement for the ping golf club was the application of investment casting in the manufacture of the K Series Irons.