Mitutoyo make Micrometers and have a lot of information on their website. The mechanism for applying constant force has a couple of options - Ratchet, Applies the lowest level of force 5-10N, makes a sound when correct pressure is applied, but isn't suitable for one handed use. - Ratchet Thimble, Applies slightly higher force 7-12N, doesn't make sound when correct pressure applied, but is suitable for one handed use. - Other options that have other compromises There are analog, digital and both types of readouts. - Mitutoyo 293-821-30 looks like a good base model digital+analog output type that uses a ratchet mechanism. Available from [RS](https://au.rs-online.com/web/p/micrometers/8336436) or [E14](https://au.element14.com/mitutoyo/293-821-30/micrometer-digital-0-25mm/dp/1276593) or [Amazon](https://www.amazon.com.au/Mitutoyo-293-240-30-Digimatic-Micrometer-1/dp/B00LFO9AVA/ref=sr_1_1?crid=2K1V3W2DWY45N&keywords=mitutoyo+293-821-30&qid=1652910630&sprefix=mitutoyo+%2Caps%2C291&sr=8-1) - We have the [Mitutoyo 103](https://www.au.mitutoyo.com.sg/au-en/product/detail/outside-micrometers-0aac4a) (103-137) series analog micrometer. It is a good quality micrometer that works well for the foam orthotics for Paromed. [RS](https://au.rs-online.com/web/p/micrometers/0572088?gb=s) Sydney Tools also has a range of micrometers - [Digital](https://sydneytools.com.au/product/daytona-ddm025-025mm-range-carbide-face-digital-micrometer) $139 - Paromed bought this one and it doesn't work very reliably for their foam orthotics () - [Analog](https://sydneytools.com.au/product/accud-ac32100101-25mm-1-metric-outside-micrometer) $55 - Kieren bought one of these and it works well.