Regarded as of one of the most advanced electronic flash in the world, the Sunpak 433D is designed to give you the best enjoyable years of service. The 433D offers autozoom and many other helpful features. Designed for several cameras in different models. Each model is designed to match the electronic flash circuitry of the respective AE SLR camera with which it is used, automatically setting the camera's shutter speed and illuminating the flash ready light inside the camera's viewfinder.