The Acute2 and 2R generation of 1200 and 2400w/s symmetrical/asymmetrical power packs have faster recycling times and significantly shorter flash duration than its predecessors. Control improvements include proportional modeling light adjustments, an On/Off switch for the photo pack and an On/Off switch for the photo slave. The packs offer multivoltage capabilities, you can use the packs anywhere in the world. Profoto heads are identical in size to the previous generation but offer a brighter 250w modeling light that using the standard mini-can base as in the Pro 7. There is also a revised Acute2 Twin Head with a 500w modeling light and an Acute2 Ringflash. The heads are fully compatible with earlier generations of Profoto Acute. The original Acute heads work well with the Acute2 packs and conversely, the Acute2 heads also work well with original Acute packs. However, the original Acute has no modeling light control at the pack. The modeling light will be on full power when using the Acute2 head on an older Acute. Lighting accessories are fully interchangeable. The 1200 power pack produces a Guide Number of 592 (180m) at ISO 100 with a 50 degree magnum reflector and a flash duration range from 1/560 to 1/3200. Product Description: Profoto Acute2 1200 - power pack Device Type: Power pack Max Flash Energy (Joules Ws): 1200 Ws Input Voltage: AC 120 V, AC 230 V Head Outlets Qty: 3 Flash Energy Range: 1200 - 37.5 Joules / f/6 Recycle Time (Full Power): 1.5 sec (AC 120 V), 1.6 sec (AC 230 V) Flash Duration (Full Power): 1/560 s