These are AWG. The question is more complicated than you think though because different lugs have different body thicknesses, so the only constant is the inside diameter of the lug which has to match the wire gauge. The outside diameter of the lug varies with the lug you are using. You need to match the crimper to the lugs you are using. I have used this crimper with both the Ancor and Pacer lugs that I sell and found it very satisfactory. Ancor used to sell a less satisfactory one before but this one is a huge improvement.