My niece's home was built with a circuit breaker box built by a long-defunct company called "Zinsco." Actually, my home and my in-laws' home also have Zinsco boxes. This company's equipment is quite ubiquitous in homes built in our area of California in the 1950's and 60's. Recently my niece overloaded one of the circuits in her kitchen by using a combination of appliances that she apparently had never used at the same time before. At first this didn't seem to be a big deal, as I easily determined how she managed to cause the circuit breaker to trip when she called me. She told me she went to her breaker box and had tried to reset the circuit breaker, but still had no power on that side of her kitchen. I talked her through resetting the breaker a second and third time, each time having her be sure to really bring the breaker switch down to the off position has hard and far as she could prior to pushing the switch back to the on position. After the third attempt the circuit that was out then had power once again. Knowing that her house had been built in 1975, and having replaced two other circuit breakers (and a neutral / ground bus bar that was actually broken!) for her, I felt this current breaker situation was in need of attention. I told her to not do anything to cause that breaker to trip again and to not shut it off, and I would order a replacement breaker and install it when it arrived. That brings me to this review: The breakers I've been using as replacements are brand new ones, made by Connecticut Electric for these old Zinsco circuit breaker boxes. It is becoming extremely difficult to find any new-old stock Zinsco brand breakers, and to be perfectly frank I don't think buying and using Zinsco brand breakers (even new-old stock) is a good idea. Since any Zinsco brand breakers were designed and made so long ago, whatever testing they met at the time does not meet the equivalent of what the Connecticut Electric breakers meet today. In fact, if you do a search on Zinsco breaker boxes you will find a number of sources of problems that people have had with them over the years, some of them have been serious. But, in fairness to the design and build quality of these boxes, in the three breaker boxes I have immediate access to, I have seen none of the problems that some Zinsco boxes have experienced. I tend to believe that the majority of the problems noted are probably due to poor or incorrect maintenance and / or repairs. All I've needed to do was replace old and tired circuit breakers when they needed replacement (my nieces' home is 46 y.o., my in-law's home is 54 y.o. and my home is 64 y.o.). There is nothing wrong with this particular new Connecticut Electric breaker, other than it was the wrong one for what we needed in my niece's circuit breaker box. Why? Mostly it's my fault because I trusted the picture on the Amazon web page that I purchased it on, instead of reading the entire description and then double checking on the Connecticut Electric web site. The problem? I needed a replacement "dual, tandem single-pole" circuit breaker with separate throws, and this breaker (UBIZ0220) is a "dual, tandem double-pole" circuit breaker with a "common-throw." Big difference! This breaker could have been used to replace the old tandem breaker, but that would mean that if something caused the breaker to trip on one side of the kitchen then both sides of the kitchen would be shut down. Not a catastrophe, but not what we wanted. The Amazon page selling this breaker has the wrong picture (I went back and checked), showing a separate-throw breaker. I'm keeping it because all of our breaker boxes use these breakers as well as the separate throw ones. I've already ordered, received and installed the new breaker in my niece's breaker box, so she's in good shape now. Just don't rely on the Amazon page pictures (and no, I saw no disclaimer that the picture might not be showing the actual breaker I was buying). As for the Connecticut Electric breakers themselves? They are great, work perfectly, are reasonably priced and are readily available for circuit breaker boxes that were made decades ago!