5 pieces of Brand New, 5/16” shank, 1" Long length of cut, 2-1/2" overall length, 40 degree helix, micrograin carbide end mill. Uncoated, and center cutting. This premium, high helix end mill will devour aluminum. Tool has a cylindrical land to improve surface finish of your part, which is held to twice as close a tolerance as our competitors. Tightly controlled Radial Rake improves end tooth strength.