Choosing the right Caliper

The 10 inch stainless steel caliper is lighter and smaller.Weighing only 2 oz. When it's fully open it can reach almost 20 inches which is large enough for general drafting on letter size up to A3 size. I't's the right choice for designing directly on the computer screen.
This is the one chosen by artists who need to carry the caliper on the road and need something compact and light.

The 13.5 inch caliper is much heavier and fully open it reaches 27 inches.
Woodworkers prefer this tool because it's larger and fits well if your hand is rather large..

All calipers may be used "at the distance" measuring large things such as a tree or house...or the right spot for a piece of furniture. This is done by looking through the caliper closing one eye, while distant from the object you are measuring.

The four arm gauge is a very useful tool for certain spcific tasks.
It's less intuitive but more precise. Specially measuring tiny progressions. It may be used by clay sculptors, plastic surgeons, dentists, etc. Also it's a good complement to the standard caliper.