QMB Series Thermal Circuit Breakers Qualtek Electronics QMB Series Thermal Circuit Breakers feature plastic M11x1.0 thread or snap-in bushings, maximum interruption capacity of 1000A, .250 quick connect tabs, and an operating temperature range of -10°C to +60°C, as well as front panel and snap-in mounting options. The devices are cost effective in consumer products, home appliances, telecom, medical, toys, motors, power supplies, marine, power strips, and transportation applications.