Physical length is differnt from the travel length 50,100,150,200,250,300,350,400,450,500, 550, 600,650,700,750,800,850,900,950,1000mm 5um. 2 axis dro digital readout display meter for milling lathe machine linear scale notice it is compete dro kits with parts to fit mounting. If you receive defective item, please kindly notify us within 14 days.