Thread Profile Gauge External (Go & Nogo) Size - 39 X 3 Mm (Ring Gauge). Wear Limit - 0.5 Mm. Ref. Drg. No. W/Bd 353 Material - Tool Steel/ Stainless Steel & Hardened Supply With Calibration Certifi Cate Valid For Min. 01 Year Issued From Nabl Approved Lab [ Warranty Period: 30 Months After The Date Of Delivery ] ]