Explorer XT 115 volt AC/60Hz model with bag, for $389, can handle up to 2400 watt-second power supplies. Has TWO, 12-volt, 12-ampere-hour sealed batteries, gives 1,000 full-power flashes with a 300-watt second monolight.
Download the manual here
http://www.innovatronix.com/tronixmanuals/Product Manual_Explorer XT.pdf
You can buy it without the carrying bag for $349.
The other option is on page 4 of their on-line catalog. The "Tronix Exlporer", also known as the Tronix Explorer 1200 model. This unit is only $319 solo, or add another $40 for the carrying bag. This currently has a $20 shipping discount, and free shipping on the bag. The normal shipping cost is $45. It has ONE 12 volt, 12 ampere-hour battery and will also do around 1,000 full-power flashes with a 300 watt-second monolight, but will not power 2,400 watt-second power supplies, and the recycle times are slightly slower on more-powerful flash units. For normal-powered flash units like a 400-wat-second power pack, the Explorer 1200 model I own is pretty close to 110 volt household AC recycle times. The 1200 model will handle a single ring light flash with no problems,especially if your shoots are under 600 flashes,and you do not need the faster recycling of a dual-battery system.
You want the 115 volt AC/60 Hz models for use in the USA. Read about the ORIGINAL model, the 1200, here
Rob Galbraith DPI: Tronix Explorer 1200 delivers on its promise of bargain performance
The manual for the Tronix Explorer 1200 states that, "with the battery fully charged most flash units will have recycling times 50% faster than what is stated in this guide", and then goes on to provide what I would call worst-case scenario specifications, which are as follows: At 150 w-s 2,000 flashes at approximately 1-2 sec recycle time. For 300 w-s flash,performance is 1,000 flashes at apprx. 3-6 sec. recyle. With 600 w-s flash, it's 500 flashes with apprx. 8-15 second recycle time--and those recycle times are "worst case scenario"....I have a 300 w/s monolight that takes 4.2 second to recycle to full power, not 8 to 15 seconds. But if the battery were almost dead, it would take longer than 4.2 seconds to recycle.