Panel mount circuit breakers are currently available in amperage ratings of 10, 15, 20, and 30 amps. Panel mount breakers will protect both 12 volt and 24 volt circuits form short circuits and over-current conditions. These breakers are Type 3, which means they are manually resettable. The top of the circuit breaker contains a reset button with the breaker's amperage rating printed on the face. When a panel mount breaker trips, the reset button will pop out, indicating the over-current condition. Once you fix the problem, simply press the reset button back in to reset the circuit breaker. These manual reset breakers are thermal by design, which means that the two connecting elements inside the circuit breaker will heat up and separate during an over-current or short circuit condition, interrupting the current flow and protecting the circuit and wiring. Because they are thermal, it also means that the breaker could have a trip current tolerance of +/- 30% over its operating range (-23°C - 65°C (-10°F - 150°F ). This is fine for almost all electrical circuits found in automotive, boat, and RV applications. These circuit breakers are designed to be panel mounted so that basically only the reset button is seen from the front of the panel, while the body of the breaker and the wiring are hidden behind the panel. Maximum voltage rating of 32 Volts DC and up to 250 volts AC. RoHS compliant and meets UL standard 1077 and CSA C22.2 No. 5.1-M91a.