Easily and securely mount signs to NEX or square tube posts and brackets. Tamper resistant. Largest diameter drive rivet available in the traffic industry, 39% larger head than competition. Easy to install. Zinc plated for strength and corrosion resistance. One blow with a hammer provides tamper proof attachment. Replace the nuts, bolts and washers with just one economical fastener. No wrenches. UV resistant black nylon washer included. Diameter of the rivet head supports sign from tearing off during high wind gusts.