We have improved the water sealing capabilities of our rivet by replacing the small rubber washer with a much larger countersunk foam membrane. This is the industry standard structural tri-locking rivet. Black anodized finish. Designed with a grip thickness range of .375" to .562". Roto-molded kayaks are about .200" thick, so the part you are riveting must be between .175" and .362" thickness. If the part is too thin, the mandrel will not break off flush. If the part is too thick, the rivet will not grip. The rivets may be installed with standard POP rivet tools. A good choice for installing our deck loops.