D1 Studio Kit 500/500/1000 Air US You know exactly what you're going to get with the D1 monolight. It's a solid all-rounder that delivers best-in-class performance time after time, a great step-in monolight. That's why thousands of satisfied photographers throughout the world rely on it for consistent power, color output and reliability. With a 7 f-stop power range and short flash duration, its performance stacks up well against many of the high-end studio packs. If you're looking for a proven, dependable performer that won't let you down, look no further than the D1.