Which of the following descriptions regarding the handling of a micrometer is wrong?
① Measure the workpiece by sandwiching the workpiece with the entire measuring faces
of the anvil and spindle.
② Handle with care, not to drop it and apply a shock.
③ Clamp the object and turn the spindle, not use the path in usual.
④ Keep the spindle in close contact with the anvil hen the micrometer is not in use,