Ratchet-Stop Thimble—Ratchet-stop thimbles have a constant-force mechanism to ensure repeatable measurements without relying on operator feel. They also have a speeder knob to reduce the time it takes to move the spindle. Once the spindle contacts the surface of the measured object, it will stop tightening, but the speeder knob will continue turning with a clicking sound.

Plain Thimble—Plain thimbles turn freely without friction or a stopping device and rely on operator feel for accurate measurements.

Nonrotating Spindle—Nonrotating spindles prevent scratches on delicate work surfaces and eliminate distortion of soft or elastic material.

Locknut—Locknuts lock the micrometer’s spindle in place.