You can do the same things with this caliper that you can with a regular 4' long caliper, except this one weighs less than 2 oz and is only 5" long when closed. More important, you can do more things with this one. For example, you can measure length and width and retain both dimensions for direct transfer to your cutting stock.
As you open the caliper, the jaw and keeper bar move together. Once you have measured the length, you can move the jaw forward to measure the width (or any distance shorter than the length) and the keeper bar will hold the first measurement as you make the second one.
You can then transfer both measurements to your stock without having to convert them into numbers, the greatest source of errors in woodworking. Just hold the caliper on your work, mark along the jaws and cut to the lines marked.
It is both easy and exact. No more stock cut too short, whether the measurement transfer is an inside measurement, an outside measurement, or one of each. A great addition to measuring tools.