M3786/4-0871 is a multi-deck rotary switch manufactured by Grayhill, designed for demanding military and industrial applications requiring reliable switching performance. The switch features a 1-inch diameter with 1-amp rated capacity, rugged construction, and is qualified to MIL-DTL-3786/4 specifications, ensuring operation across extended temperature ranges from -65°C to 85°C (unsealed styles) or -65°C to 125°C (sealed styles). Key technical characteristics include contact resistance of 50 milliohms maximum, insulation resistance of 1,000 megohms minimum between mutually insulated parts, and dielectric strength of 1,000 Vac minimum at atmospheric pressure. The switch accommodates multiple deck configurations (1 to 12 decks), with adjustable stops, shaft/panel seal options, and PC termination available. Common applications include military equipment, aerospace systems, and industrial control panels where durability, low-level switching capability, and shaft grounding are critical requirements.