If you are looking for a non-rotating depth micrometer, the Starrett 449AZ-3R Depth Micrometer is the tool to have. It offers accurate measurements of the inside and outside diameters of cylinders, holes and recesses. With a combination ratchet and speeder for uniform pressure, this depth micrometer allows you to quickly adjust it with ease. The flat spindle has a zero setting at any point on its travel length. The zero mark on the thimble remains in position when resetting or changing measuring anvils. This 0 to 3" range micrometer has a resolution of 0.001".

If you need high accuracy measurements without needing to readjust your gage, this Starrett Depth Micrometer is what you should go for.