The 91C1D-E20-B15L is a 5/8" square single-turn panel control potentiometer manufactured by Bourns, featuring a 100 kO resistance value with linear taper (E configuration). This component is part of the Model 91 series and offers virtually infinite electrical circuit isolation with available metal or plastic shaft options. The potentiometer is RoHS compliant and designed for applications requiring reliable resistance control in audio and signal processing equipment. Its compact 5/8" square form factor and single-turn design make it suitable for panel-mounted control applications in consumer electronics, industrial equipment, and audio systems.