M3786/4-0003 is a multi-deck rotary switch manufactured by Grayhill, designed for Series 42, 43, 44, and 54 configurations with a 1-inch diameter and 1 ampere current rating. The switch features rugged construction ensuring reliable operation throughout the equipment's service life, with military qualification to MIL-S-3786/04 and UL recognition. Key technical characteristics include a 3/8-32 UNEF-2A thread mounting, bushing keyway dimensions of 0.066 ± 0.002 inches wide by 0.036 ± 0.003 inches deep, and a non-turn tab measuring 0.125 ± 0.003 inches wide by 0.031 ± 0.003 inches thick. The switch supports multiple deck configurations (1 to 12 decks) with corresponding dimension variations, and offers various circuitry options including shaft/panel seal, adjustable stops, and PC termination. This switch is ideal for military equipment, aerospace applications, and other demanding environments requiring high reliability and precise switching control.