Spiral router bits are made by Amana Tool, the leading manufacturers of high quality wood cutting tools. Amana Tool 46094 SC Spiral 1/4 D x 3/4 CH x 1/4 SHK x 2-1/2 Inch Long Composite, Fiberglass & Phenolic Cutting ZrN Coated Up-Cut Router Bit incorporates high shear, multi-fluting and Zirconium Nitride (ZrN) coating designed for the ultimate combination of finish and tool longevity in aerospace materials. Excellent for: Plastic, Acrylic Stone, Aluminum, Acrylonitrile-Butadiene-Styrene (ABS), Carbon Fiber Reinforced Polymer (CFRP), Coroplast, Corian, Fiberglass, Fiberglass PCB Board, HDPE, High Impact Polystyrene (HIPS), Lexan?, Low Density Polyethylene (LDPE), Phenolics, Poly (methyl methacrylate) (PMMA), Polyethylene Terephthalate Glycol-Modified (PETG / PET-G), Thermoplastic Polyolefin (TPO). SPECIFICATIONS: Direction: Up-Cut; (D) Diameter: 1/4; (B) Cutting Height: 3/4; (d) Shank: 1/4; Overall Length (L): 2-1/2; Flutes: 3.