Weight: 170g Ring width: Approximately 7mm Ring size: #1 to #30 Made of zinc die-cast, nickel-plated finish Flat-type ring gauge Recommended for those considering purchasing a thick ring. Please use a dedicated ring gauge for the flat type, which is slightly different from the usual thin type ring sizes. MKS size gauges are inspected according to national standard specifications, and each one has a pass inspection sticker. They are used as standard in shops throughout Japan.