This is a quality, high grade, galvanized 1/4" ISO G4 chain by 4' long with two galvanized 5/16" bow shackles with oversized pin. Suitable for use in a windlass as anchor chain or other marine applications where high corrosion resistance is desired. Superb for anchor chain and general heavy duty work in a marine environment. This chain will fit many standard windlasses. Please consult your windlass manufacturer model manual for the ideal specification for your windlass. The 3 important figures for smooth running or your windlass is the Diameter (DIA), Inside Length (IL) and Outside Width (OW). More details are in the spec table below. This chain is 0.27*0.85*0.94 (DIA*IL*OW). The measurements of this chain are listed in inches.