Rotary Shouldered Thread Gauges - Northern Gauge Northern Gauge manufacturers API 7-2 working gauges. All gauges include a certificate of calibration that has traceability to an API-certified reference master. We have the most extensive API 7-2 reference masters on hand in Canada. Read More - https://www.northerngauge.com/api_thread_gauging/api-7-2-rotary-thread-gauges/ Address - 202 Tideland Road, Broussard, Louisiana USA 70518 Email ID - salesusa@northerngauge.com Contact Number - 337-426-1992