1.表圈轉(zhuǎn)動圈為金屬外圈 Adjustable steel dial ring. 2.帶公差指示器 With adjustable tolerance markers. 3.帶表圈緊固裝置 With dial locking screw. 4.可同時(shí)進(jìn)行公、英制讀數(shù) With mm and inch reading.