Check if a can is properly sealed by inspecting the width, height, and depth of the seam. Balance the end of these micrometers on the rim of the can to take measurements with one hand. Their ratchet thimbles have a speeder knob to reduce the time it takes to open and close the micrometer. When the spindle stops tightening, the thimble will continue turning with a clicking sound.

Style B micrometers have a lip on the spindle for getting into grooves, such as those found on the top of a drink can.