Here's what other sites are saying:
The Goal Zero Extreme 350 Power Pack allows you to live life off the grid, camp in luxury, or power through an outage without the noise and fumes of traditional back-up generators.
Store power from your solar-powered base camp, or use the Extreme 350 Power Pack as a battery backup when you're far from the grid. This Power Pack serves as an add-on to your Extreme 350i Power Pack and Universal Inverter to boost the power you can have on hand to keep your electronics charged and light up the night. A tough casing, rubberized handle, and highly weather-resistant construction mean you can put this pack through the paces from Everest to your base camp in the desert.
Goal Zero Extreme UI - AC Inverter
Goal Zero Guide 10 Power Pack
Goal Zero Escape 150 Power Pack
Goal Zero Ranger 350 Adventure Kit
$37 - $149
Goal Zero Sherpa 50 Recharger
$200 - $449
Goal Zero Guide 10 Plus Recharger
FlameStower Heat Charger