1.用于测量不同管壁的厚度 For measuring the thickness of different tubes. 2.壁厚千分尺测量面组合:长腰鼓面-平面(D型) Type D 3.除0-25mm(1")规格外,其他规格提供一个校对杆 A calibration rod is supplied for range above 25mm(1").