I needed to add some circuits to a complete panel and as this panel was manufactured in the early sixties I had difficulty finding the correct circuit breakers to fit my panel, which is an ITE model. Tried to buy locally but could only find switches with protective covers so they don't fit in a switch bay. These switches fit right into the old panel with no modifications and should not be used in panels designed for circuit breakers that use the protection I mentioned. Fits perfectly and did what I needed to do!