They are made of high strength aluminum with a captive stainless cross-pin. Halyard line can be permanently spliced, but the all-metal thimble also allows for use as a 2-1 purchase without the wear or melting that occurs with plastic molded thimbles. The clevis slot size is made to fit standard headboards without adding unnecessary weight. The strength and weight have been optimized by computer modeling and verified by numerous "make and break" tests.
Machined from a solid block of aluminum
Type III hard coat annodized for corrosion resistance
Captive 17-4PH stainless steel pin resists wear and bending while allowing full throat width of the clevis for passing over headboard
Every shackle is factory pull tested