It is durable and scratch resistant. Standard Size 18-20mm snap interchangeable jewelry that features "fashion snaps" -- button-like charms you snap in and out of stylish bracelets, rings, Sun glasses and more! You can create and re-create jewelry that expresses YOUR personality, any way you choose! There's a snap for every personality, every style, and every occasion. To change your Snaps, simply pry out using your finger. The Snap will detach from the finding and can quickly be removed and replaced with a new design. Length:20" + 2.5 Extender length of Pendant: 6cm Weight: 20g Chain: Ball Metal Alloy Environmental Standard:Lead Nickel free