Connecticut Electric manufactures new high quality replacement circuit breakers for Zinsco load centers that accept Zinsco Q style circuit breakers. Circuit breakers should only be replaced with new tested and Safety Agency Listed circuit breakers, never used or refurbished ones. From the Manufacturer This 120 volt Zinsco 40 amp, single pole, thick series replacement circuit breaker is used in a Zinsco load center. Typical applications, up to 3,600 watts, include well pumps (up to 200'), bathroom heaters and electric motors (1-1/2 hp to 2 hp). These are only suggested applications and cannot assure compliance with all local codes. Please check local electrical codes before starting any electrical project.