This Chainsaw file by DMT uses quality monocrystaline diamonds for fast sharpening. Use light pressure and let the diamonds do the work for you. Not only will this sharpen chainsaws but it works great on curved knives and serrated blades. Made in the USA. The diamond surface of the DMT Chainsaw Files is 3 3/4" long. The overall open length is 9 1/2", the closed length is 5". Q. How do I know which size file I need for my chain? A. A chain's original packaging should list the specific size file required for its sharpening. However, if you do not have the original package, you can usually determine which file you need by locating the pitch of the chain, which is often stamped on the chain's side. While not universally true, typically pitches of 1/4" or 3/8" Low Profile use a 5/32" diameter file, a pitch of .325" uses a 3/16" diameter file and pitches of 3/8" or .404" use a 7/32" diameter file.
