ISOFits is an application for measuring linear dimensions, which allows you to measure and calculate the lengths of tubes, bars, and other linear dimensions up to 100mm in length. The measurements are based on a nominal diameter, which is the same for all tubes, regardless of their size.

The measurements are made using a dial gauge, which is a type of dial meter. It is an instrument used to measure the length, diameter, and thickness of a material, and it is designed to be used for measuring in a metric or non-metric environment. 

ISOFits is designed to make the measurements quick and easy to perform, even if you have never used a dial gauge before. All you need to do is select the measurement type (mm, cm, inch), select the tube or bar to be measured, and tap on the screen. You can then start the measurement. When the measurement is finished, you will be able to see the results, the length of the tube or bar, as well as the diameter and thickness.