Twist-Rope Overhand Love Knot 6x8mm (1/4x1/3in) Charm Sailor's Promise Ring in Oxidized. 925 Sterling Silver. The featured ring is cast in oxidized-finish. 925 sterling silver and showcases a twisting-rope band crafted to create a 6x8mm (1/4x1/3in) overhand knot centerpiece finishing into a thin band.