Whiteside RU4900 Up Cut Spiral 1/2"SH, 3/8"CD, 1-1/4"CLWhiteside RU4900 Up Cut Spiral 1 2"SH, 3 8"CD, 1 1 4"CL Product Description Spiral bits provide a shear cutting edge that leaves a smoother cut than standard router bits. Up cut spiral design provides the best control with hand or table routing. When creating dado's this design brings chips up and out of the cut. Materials: Natural woods, composites, hard plastics, thin aluminum Recommended RPM: 16,000 18,000 (max 24,000)