Regina Chain 520 ZRD Series Chain - 100 Links - Gold 135ZRD/100 New ZR series chains feature high-performance Z40 sealing rings, which dramatically improve performance and wear life; make obsolete all previous X- and Z-ring chains Features high-carbon alloy pins to minimize wear and increased roller thickness to prolong life Thicker outer plates and foursided riveting mean greater average tensile strength Gold outer plates and black rollers