Measure the thickness of paper and other thin materials without distorting them. These micrometers have disc-shaped tips and a non-rotating spindle that apply soft pressure on delicate parts. A ratchet-stop thimble with a speeder knob reduces the time it takes to open and close these micrometers. When the spindle stops tightening, the thimble stops turning, but the speeder knob will continue turning with a clicking sound.