1.用于測量不同管壁的厚度 For measuring the thickness of different tubes. 2.壁厚千分尺測量面組合:長腰鼓面-平面(D型) Type D 3.除0-25mm(1")規格外,其他規格提供一個校對桿 A calibration rod is supplied for range above 25mm(1").