It's well built too. This turns your caliper into a depth gauge. (Here I use the word "tool" very carefully.) I can use it for multiple applications, but I had to buy a depth gauge for a specific application. I bought a Starrett 440Z-3RL. I bought Sturrett products because they are made in America (not made elsewhere, just assembled in America) and assembled. Yes, they are made and built right here in the USA. I emailed Starrett for information and it was great working with them via email. So, I'd say if you want a sturdier work platform (like I do) get a depth gauge. I wanted to measure the depth of the primer from the head of a metal cartridge. Depth mounting does not work well with a caliper. This app requires a depth gauge. If you decide to use a depth gauge for this type of application, you will need to secure the cartridge in a block of wood or ammo box to ensure it is stable. My 440Z-R3L gave me varying depths on my capsules, but gave me consistent readings on a given cartridge every time.