The XB4BA21 is a complete spring-return push-button from the Harmony XB4 range, featuring a black flush, unmarked operator profile. It is designed for a 22.5mm panel cutout and is constructed with a durable chromium-plated metal bezel and Zamak fixing collar. The device includes a single normally open (1 NO) slow-break contact with silver alloy material and connects via screw clamp terminals. Key electrical ratings include a 600V rated insulation voltage and 10A conventional free air thermal current. With a mechanical durability of 10 million cycles and high IP ratings up to IP69K, this push-button is built for reliability in harsh industrial environments.