Notes: ^A In the 2.4 GHz bands bonded 40 MHz channels are uniquely named by the primary and secondary 20 MHz channels, e.g. 9+13. In the 5 GHz bands they are denoted by the center of the wider band and the primary 20 MHz channel e.g. 42[40] ^B In the US, 802.11 operation on channels 12 and 13 is allowed under low power conditions. The 2.4 GHz Part 15 band in the US allows spread-spectrum operation