Running boards can be used on both sides of the vehicle, the left and right, they are usually located in the lower part of the vehicles. Its function is very simple, they serve as support to enter a truck, especially for those who have a large height or have oversized tires.
At the same time, running boards can also protect vehicles from road debris, this would be a secondary function.
The last benefit they have is cleanliness, but this would only be something additional.
Running boards are usually built with the following materials:
Fiberglass and Platics
Remember that the main function is to use them as stairs so keeping them clean and dry is imperative, otherwise it could lead to slips and cause injuries.