The License-Exempt Spectrum:

Band Range          Maximum Power                Usage Area

ISM  2.4-2.4835     1 watt max                   indoor and outdoor
UNII 5.15-5.25      50mW or 4dBm+10LogB          indoor ONLY
UNII 5.25-5.35      250mW or 11dBm+10LogB        indoor and outdoor
UNII 5.725-7.825    1 watt max or 17dBm+10LogB   indoor or outdoor
ISM  5.725-5.850    1 watt                       indoor or outdoor