Moveable guards are a common risk reduction strategy for most applications. Machine builders need general-purpose, robust safety door switch that will work with a variety of movable guards and in a variety of environments. The D4BS series is a key-operated door switch that offers a robust metal housing making it ideal for heavy-duty applications. This series offers two different contact configurations, 1NC/1NO, and 2NC; models with 1 or 3 conduit openings, operation keys options, and support a wide temperature range.