Threaded Ring Gauge Long Form Calibration Certificate No Material Tool Steel Dimension Type Metric Gauge Type Go/No-Go (Plus/Minus) Pitch Diameter 18.334 mm (Go) 18.164 mm (No-Go) Pitch Diameter - Go Member 18.334 mm Pitch Diameter - No-Go Member 18.164 mm Thread Class 6G Thread Length 19 mm 14.3 mm Thread Size M20 x 2.50 Thread Type Metric Compatible Holder Size 4T Finish Uncoated Gauge Design Adjustable Hardness RC 60-62