Materials: Stainless steel. Measurements: Length 7.5" + 2" extender chain, width 5 mm. Closure: Lobster clasp. Allergy Information: Hypoallergenic. Care: Our jewelry is pretty low maintenance, but to keep your jewelry looking its best follow our below recommendations. Dos: Store jewelry separately to avoid scratching. Wipe away dirt and oil buildup with a soft cloth - preferably a microfiber, or jewelry cloth. Dirt and oil buildup will temporarily darken the appearance of the jewelry unless cleaned properly. Donts: Avoid direct contact with chemicals (lotions, perfumes, ETC) as both will contribute to fading. Do not sleep in delicate necklaces.