An extremely important accessary for almost all professional applications, the Power Winder II frees the photographer from the need to manually activate the film advance/shutter cocking mechanism. This lets the photographer concentrate fully on the subject, while the motorized winder takes care of film, shutter and mirror settings. Single-frame or sequential film advance (1.5 sec. per frame); the Power Winder II is powered by six AA type alkaline cells (500-600 consecutive shots are possible), or six Ni-Cad batteries (300-360 consecutive shots are possible). An optional 9V AC adapter is available. For all rollfilm magazines.