The ZB4BG2 is a keyed selector switch operating head from the Harmony XB4 range, designed for standard 22mm mounting applications. It features a black key switch operator with two maintained positions at a 90° angle, utilizing a Key 455 which can be withdrawn in the left position. This robust head is built with a chromium-plated metal bezel and offers a high mechanical durability of 1,000,000 cycles. Its high resistance to vibration, shock, and environmental factors, confirmed by IP ratings up to IP69K and a wide operating temperature range, makes it a reliable component for industrial control panels and machinery in harsh environments.