This B2 250 Air TTL To-Go Kit from Profoto is an ideal way to get into the game-changing battery-powered flash system that includes the B2 250 AirTTL Power Pack, Flash Head and tailor-made OCF (Off-Camera Flash) accessories. The kit includes the pack, a battery, charger, 1 B2 flash head, padded Location Bag and a Carrying Bag with shoulder strap. Complete the kit and get full wireless TTL operation with the purchase of a dedicated AirRemote TTL transceiver for your Canon or Nikon Camera.Intended for the road, the B2 250 AirTTL Power Pack measures 6.3 x 3.1 x 6.7 and weighs in at just 2.2 lb with its Li-Ion battery. The B2's twin outlets each have a dedicated thumbwheel that allows the pack's 250Ws of power to be distributed asymmetrically over a 9-stop range in full or 1/10 steps.The digital LED screen that displays the power settings is also the key to the pack's many capabilities. The B2 boasts recycling times from 0.03 1.35 sec., and an action-stopping flash duration of 1/1,000 sec. There is also a Freeze Mode that selects a flash duration of 1/15,000 sec. at lower power settings fast enough to freeze water droplets, spray and splashes. Bursts of up to 20 frames per second are possible while High Speed Sync allows shutter sync speeds from 1/4,000 1/8,000 sec., giving you wide ambient light control options. The pack's Li-Ion battery can be charged in or out of the pack and will give you up to 215 full-power flashes on a 45-60 minute charge from a multi-voltage 2.8A battery charger or a trickle charge from an optional car charger.At 1.5 lb, the sturdily built B2 Off-Camera Flash Head measures 4 long, has a 3.9 diameter and fits in the palm of your hand. A barely-visible umbrella channel runs through the top of the head, while its tethered 6.5' head cable can be lengthened with a 9.8' extension for large groups or for hanging in hard to reach places. An included stand or pole-mount with a ratcheting handle can be removed for mounting to a flash bracket. The B2's flash tube and 50W halogen-equivalent LED modeling lamp are protected by a frosted glass plate, while its 3.9 diameter housing accepts a line of optional accessories that includes OCF-tailored softboxes, barndoors, a snoot, and a grid set. They can also be used on the B1 battery-powered monolight.