Starrett KD0400-N 4-Inch Diamond Grit Holesaw<div style="text-align: left;"><strong>[Product Information]</strong><br><ul><li>Effective cutting of hardened steels， fired ceramics， aggregate containing concrete， non-metallics and other difficult to cut materials</li><li>Clean effective cuts and extended life</li><li>Uniform synthetic diamond grit bonded over a durable steel platform</li><li>Always use a coolant and start at a low speed， increase speed as ease of cutting is noticed while avoiding heat build-up on the cutting surface</li><li>Recommended cutting speed is from 150 to 300-RPM</li></ul></div><img src="http://ecx.images-amazon.com/images/I/51lvcb8yg7L.jpg" noproxy><img src="http://ecx.images-amazon.com/images/I/51skHN7zV%2BL.jpg" noproxy>