BB3-B0-42-630-221-D is a B-Series rocker-actuated circuit breaker designed for precise protection in demanding environments. This UL489-listed device utilizes hydraulic magnetic technology to provide reliable operation across extreme temperature ranges, making it suitable for power supplies, medical equipment, office equipment, control panels, and marine applications. The breaker features a 630 mA current rating with screw terminals and operates with a rocker actuator in standard black or white color. It meets UL Standards 1077, 508, 1500, and 489A certifications, as well as CSA Standard 22.2 No. 100 for generator and welder markets. The hydraulic magnetic principle ensures consistent performance even in hot or cold environments, providing dependable circuit protection for critical industrial and commercial systems.