引伸计 Extensometer

此装置可用于测量试样的物理形变量，如拉伸测试时，试样的宽/厚度变化。
测量范围为250mm，标距为25mm。
This device can be used to measure the physical deformation of the specimen, such as the width/thickness change of the specimen during tensile testing.
The measurement range is 250mm and the gauge distance is 25mm.