GREASE NIPPLE ZERK BOLT THREAD CHECKER TESTER UNF ANF BSW NPT BSF BSP METRIC

BSF: 3/16", 1/4", 5/16", 3/8". BSW: 1/4", 5/16", 1/2". Checks a full range of threads as found on many grease nipples, bolts & engineering components.

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