Heavy 12 gauge American high standard 14K gf was hammered to yield 5" across (approx 16.5" interior including opening) 3mm wide collar. A word about this gf here; on my left hand you will find a 14k gf bracelet made 5 - 6 years ago, which is Never removed. It still looks like the real gold enchilada and has NEVER turned! Wear this gf with confidence.