The 71BS30-04A12S is a rotary mechanical encoder from the Series 71 family, designed to provide a binary coded output based on shaft position. It is rated to make and break 125 mA at 30 Vdc and can carry up to 3 amperes with a maximum contact temperature rise of 20°C. The switch features a voltage breakdown of 500 Vac between insulated parts and an initial insulation resistance of 50,000 megohms minimum. Built for reliability, it offers a life expectancy of 25,000 cycles at its rated load and 50,000 mechanical cycles. With its robust electrical characteristics and durable construction, this encoder is suitable for applications requiring reliable position sensing and manual data input in various electronic systems.