The 91A1A-B28-B20L is a 5/8" square single-turn panel control potentiometer manufactured by Bourns, available with either conductive plastic or cermet resistive elements. The device offers resistance ranges from 1 kO to 1 MO for conductive plastic elements and 100 O to 1 MO for cermet elements, with total resistance tolerance of ±10% or ±20% for conductive plastic and ±5% or ±10% for cermet. It features independent linearity of ±5% and an absolute minimum resistance of 2 O maximum. The potentiometer is available in multiple pin-out configurations and taper options (linear and audio tapers), with a metal or plastic shaft option. This component is RoHS compliant and provides virtually infinite electrical circuit isolation, making it suitable for audio equipment, instrumentation, and consumer electronics requiring variable resistance adjustment.