Trim pots are also known as preset potentiometers used for adjustment, calibration and tuning purpose in circuits. They are easily mountable on PCB boards and adjusted by a screwdriver. The resistive track is made up of carbon composition or cermet. When replacing with normal potentiometers, remember their life span is not so long. There are different types of trimmer pots available in market such as through hole, smd, single and multi-turn variation.