I'm super excited to have recently recently picked up a Profoto B1 Air TTL Off Camera Flash Location Kit. The kit consists of two 500 watt second mono block flash heads and chargers which are operated by a Profoto Air Remote that uses TTL (through the lens) metering via the camera body in order to obtain incredible flash exposures almost instantly and without the need for a light meter.
The kit comes in an awesome backpack and when combined with a couple of Manfrotto light stands and some light modifiers it is a completely portable battery powered lighting solution for studio or location work. The batteries are small and clip onto the side of each light and recharge in an hour. A fully charged battery will deliver 220 flash pops at full power (500 watt seconds is equivalent in power to 10 speed lights (on camera hot shoe flash units) at full power, and at minimum power will deliver up to 50,000 flashes. There is never a cord between the lights and the camera.
I spent an afternoon in the studio yesterday and used the kit for the first time and it was an absolute joy. Looking forward to getting them out and into the field next for some awesome location shoots.