Building on the foundation of the popular D1, the Profoto D2 500 AirTTL light maxes-out the D1 performance specs while adding wireless TTL from the B1 and B2. With the D2, "speed" is the operative word. The D2 500 recycles to full power in 0.6 seconds, almost half the time as the D1 500, and in Freeze Mode, achieves flash durations as short as 1/63,000 of a second, outperforming most studio pack systems. Also, shoot bursts of 20 flashes per second. In addition, the D2 also supports High-Speed Sync up to 1/8000 of a second for photographers who want to stop action or use wide apertures with full ambient light control. The 10-stop power range gives ample choices to achieve your objective. Besides super-fast operation, the D2 shortens your shooting time with on-board TTL compatibility. Set your lights up, set the camera to TTL and shoot. The key to this control is the optional Air Remote TTL-C (for Canon) or TTL-N (for Nikon). Operating on 2.4 GHz bandwidth, the wireless transmitter, really a controller, has 8 frequency channels and with 6 groups and a range of up to 330' for TTL triggering and 1000' for normal triggering. Each channel has power ratio capability of +/- 2 stops. If you prefer to use manual, you have 10 stops of power variation. The D2 also features an enhanced, intuitive LCD screen display. Modelling Light, Ready Indicator, Mode, Sync, Channel, and Group are easily selected through the Settings button. The D2 has a self-seeking multi-voltage (100-240) power supply for worldwide use, too.