We offer a couple of different types and sizes of these devices and find that when you need to mix a little more than just a small cupful of material they are invaluable. They work best on a 1/4" or 3/8" variable speed drill. For long lasting value the American made, heavy duty variety work best. If you need something for a short run, the economy grade will do. Medium size good for up to 2 gallons of liquid. Dimensions: Shaft = .315" Length with Head: 13.25" Length without head: 11.25" Head Diameter: 2.25"