ATC Circuit breakers are designed to replace ATC fuses in most applications. The base of the circuit breaker is shaped like an ATC fuse so it will fit into existing fuse blocks and fuse holders. The ATC circuit breakers are about twice as tall as a regular fuse, so make sure that height is not an issue before using them. ATC circuit breakers are available as Type1, Type 2, and Type 3, In an overload condition, Type 1 auto reset will cycle the circuit breaker until the overload condition is removed. Type 2 modified reset will keep the circuit breaker tripped until the overload condition is removed. Type 3 manual reset thermal non-cycling circuit breakers will remain tripped until the operator resets the circuit by pushing a button that pops out and is located on top of the circuit breaker. Type 1 and Type 2 circuit breakers are for use with 12 volt circuits only. Type 3 circuit breakers can be used with both 12 volt and 24 volt electrical circuits.