API螺纹中径测量仪

http://www.szfyou.cnAPI螺纹中径测量仪/MRP中径规 用于API 螺纹中径测量，使用前必须用螺纹标准杆校对，螺纹标准杆需要单独购买。 Measure the middle diameter of API thread. Need be presetted with the API thread standard shank.. The shanks are Sold separately from the gages.