Harken Lead Rings are simple, weight-saving devices used to route line for jib in-haulers, twings, barberhaulers, lazy jacks, cascading backstays, and other applications requiring minimal fine-tune adjustments. Rings are Hard Lube-anodized 6061-T6 aluminum for a smooth, slippery surface, and with no moving parts, wear is minimal.SpecificationsCenter hole diameter: 7/16″ (10 mm)Outer groove width: 1/4″ (6 mm)Weight: 0.155 oz. (4.4 g)