The ST-4ETA103 with 10 kOhms 0.25W is a 1/4W J Lead Surface Mount Trimmer Potentiometer (SMT Pot) manufactured by Nidec Copal. It is a Cermet (ceramic and metal alloy) potentiometer with a top adjustment knob for tightening or loosening the resistance resistance. The potentiometer has a 1.0 turn mechanical travel and has a maximum operating voltage of 16VDC. It is used in controlling the speed of motors and adjusting the brightness levels of LEDs.