The 350W output is the maximum output power in the global with a so much compact size. The GX350 mod max output power can up to 350W when powered by 4 x 18650 batteries or up to 220W when powered by 2 x 18650 batteries. And the Micro-USB port supports firmware upgrade but not for charge.
1. 300W Super power 2. Compact size and comfortable to hold 3. Two or four 18650 high drain battery 4. Firmware Upgradeable