Solid Sterling Silver Rhodium Plated 1.3mm Cable Chain Necklace - 16" 18" 20" 24" 30" 36" Unsure what length chain to buy? 18 inches is the standard length and will look great on most people. This chain necklace is made of solid rhodium plated sterling silver and stamped "925". This classic necklace is a great choice for wearing with your favorite pendant. Chain is 1.3 mm thick, comes in: 16, 18, 20, 24, 30 and 36 inches long.