The test device can be used to test steel ruler; meet JJG1-1999 steel ruler test procedures, the test procedures and alternative JJG1-1989 JJG397-1985, test methods, see the detailed verification procedures Name Quantity Remarks accuracy specification model a surface roughness set of four flat-foot level certificate containing a 1/2000 * 200 * 100mm certificate containing a semi-circular plate R = 250mm wide seat square grade certificate containing a 1 50mm * 80mm certificate containing a third-metal lined Michi 1000mm certificate containing a 20x reading microscope containing a certificate containing a feeler certificate