The Gun Screw Assortment is a carefully selected assortment of twelve each of our twenty-three most popular screw sizes. This kit is priced substantially less than the cost of buying the same screws individually. This is a great way to be sure you have what you need when you need it. Type A Fillister & Type B Oval lengths are measured from under the head. One dozen (12) of each screw type, 23 individual types total.