Buff E640 Einstein Flash Unit - 7712 flashes. Paul C Buff Einstein 640 flash unit. 9 f-stop power variability (2.5 Ws to 640 Ws). Adjustable in precise 1/10 f-stops.All-digital control from LCD display. Global plug-and-play from 95 to 265 VAC. Action stopping flash durations as short as 1/13,500 sec. Color consistency +/- 50K at any power. Bright, adjustable 250 W modeling lamp. Frosted dome cover reduces UV emission. Audible and visual recycle indicators. Compatible with all BUFF light modifiers, light stands, CyberSyncT remotes, and VagabondT systems.