This 316 Stainless Steel Windlass Anchor Chain is a true 1/4" chain (0.25" or 6.3mm). This listing is by the foot. Order the number of feet you require in the quantity box. Your chain will ship as that continuous length. This is a quality, high grade, marine stainless steel (AISI 316) DIN766 chain 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 or chemically harsh 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 6.3*18.9*21.5 (DIA*IL*OW). As DIN766 is a metric specification we list the specs in mm, the imperial equivalent of this chain is 1/4"*0.74"*0.85". The link size is 1/4" or 6.3mm metric equivalent. Every 3 feet links are hallmarked and stamped with 316.