Also referred as a Tandem, Twin, Thin 40A Gray toggles. The toggles are connected with a handle tie to achieve a 2 pole 240V breaker in one unit, the letter C designates a two pole. Zinsco was the original OEM manufacturer of this brand. These are obsolete and are only available in recondition. In the 1950's this was a very popular brand. They appear all over the USA in older homes, such as This Old House. In later years Sylvania purchased the brand, then later it was Challenger, then still it was Thomas & Betts. Today only a knock-off brand is made by Unique Breakers. Nick names like Magnatrip, QB, QFP, QFB where also part of the Zinsco group. In many cases the bus bar is damaged from overloading. We stock repair kits for some panels, so please call Breaker Outlet for details at 800-321-8998.