This 2-flute spiral bit is designed for solid wood and wood composites. While it can be used for certain plastic applications, O-flute and Z-flute bits are recommended. This bit works well in cutting Type I high density foam. A up-cut spiral bit is used where an upward chip removal and a good finish on bottom are required. When using an up-cut spiral bit, chip removal is optimized but adequate hold down is also needed. Always refer to the operation manual of your router first, in the event that a router bit doesn't come with a speed chart, you may start at about 2,000 rpm slower than the maximum speed described in the chart below. Maximum speed below is for reference only, actual best performance speed varies depending on a number of factors i.e. size of the router bit, the material to be cut, etc. Run 24,000 rpm maximum for 1" overall diameter router bits; Run 20,000 rpm maximum for 1-1/2" overall diameter router bits; Run 18,000 rpm maximum for 2" overall diameter; Run 16,000 rpm maximum for 2-1/2" overall diameter router bits; Run 12,000 rpm maximum for 3" overall diameter router bits; Run 10,000 rpm maximum for 3-1/2" overall diameter router bits;