This is a (205-240V AC) magnetic ballast for the Altman 4KW HMI Fresnel light. Magnetic ballasts are more economical than electronic ballasts, but they are much heavier, louder, and are not for multi-voltage use.
A magnetic ballast is an economic alternative to an electronic ballast, when increased weight, size and operating noise level are not crucial during use.
Recessed, bi-polar main circuit breaker.
Heavy gauge stainless steel housing, low profile handle.