This duct is the valve seat cutter and boring Cutters. Seat cutters are almost standard equipment in any machine shop that services four-stroke engines – whether the work is small engine repair, automotive high performance, routine motorcycle maintenance, or heavy duty engine rebuilding. We believe that our duct has been so popular for one simple reason: it offers value. It’s extremely easy to use, is accurate enough to be the tool of choice for high performance engine work, and it doesn’t require a huge investment. Number of pieces: 28. Suitable for: Diameter 22-63mm valve. Cutter Blade Angle: 15°, 30°, 45°, 55°, 60°, 75°, 90°. Tool bar diameter: 5MM, 5.5MM, 6MM, 7MM, 8MM, 9MM, 9.5MM, 10MM, 10.5MM, 11MM, 12MM. 14 x Cutter Blade. 11 x Cutter arbor. Welcome to our store! We are a professional worldwide wholesale company, with our own factory located in China. We will reply your message within 24 hours Mon-Sat, and 48 hours on Sunday. Feedback is very important to us. I will do my best to solve the problem, thanks!