In this simple example, dCal shows the weight difference between 100 steel, aluminum, and nylon bolts of the same size.
To make this example project, all I had to do was select the bolts from a drop-down menu, and enter a quantity of 100 for each of them. If you know how many bolts your project uses, dCal can tell you how much they'll weigh in steel, nylon, or aluminum. The database will have many sizes, in each material.
There are many times you can use nylon or aluminum bolts instead of steel and this example demonstrates how much of a difference they can make. I'll expand on this post in the future.