The 91C2D-E20-H10/H10L is a 5/8" square single-turn panel control potentiometer manufactured by Bourns, featuring a metal shaft (Type H) with standard length options of 19.05 mm (0.750") or 22.23 mm (0.875"). This model is available with various resistance tapers and element types, including conductive plastic and cermet elements, with resistance ranges from 100 ohms to 1 megohm depending on the taper configuration. The potentiometer features an "A" style A.R. lug for mounting, with a bushing diameter of 13.72 ± 0.38 mm (0.540 ± 0.015"), and is designed for virtually infinite electrical circuit isolation with RoHS compliant versions available. These panel controls are commonly used in audio equipment, instrumentation, and industrial control applications where reliable, single-turn adjustment is required.