Snaps fasteners with longer posts for thicker fabrics, leather or carpet. The post on the Cap is 5/16" and the bottom Eyelet post is 3/8". All parts are Nickel Coated Brass. These snaps are marine grade and are corrosion and rust resistant. Northwest Tarp and Canvas will sell only top of the line quality items and will never settle for less than the best for our customers. Guaranteed Fast Shipping! Northwest Tarp and Canvas Bellingham, Washington USA