When you need accurate control over rigging settings on performance yachts and non-marine applications, you can rely on Ronstan calibrated Sealoc turnbuckles. Engraved millimeter markings. Available as a complete turnbuckle for new installations or body only for replacement of non-calibrated bodies in existing rigging. Available in 1/4", 5/16" and 3/8" U.N.F. thread sizes to suit swage terminals for 1/8" to 7/32" and 4 & 5 mm wire. Ideally suited for "off the beach" catamarans, trailerable yachts and small keelboats such as E22's, J24's, Solings and Dragons Melges 24's Johnson 18's.