The only relevant Countries / Regions in my opinion. I was bored so I went thru them all. Internet connection is sometimes lost after a save in Advanced-Wireless, if that happens just go to Advanced – LAN Access and click Save or reconnect power to the router (reboot will not be enough). BOTSWANA (BW), LIBERIA (LR), SAUDI ARABIA (SA), UGANDA (UG) and SAMOA (WS): Max TX Power 2.4GHz = 35mW (15.50dBm) Max TX Power 5GHz = 50mW (17.00dBm) (ch.36-64), 63mW (18.00dBm) (ch.100-165) Number of 80MHz channels = 6 If Transmit Power is set to 0 the wireless driver will use Max TX Power. Setting Transmit Power to 28-35mW for the 2.4GHz band should give the 5GHz band priority in most cases and still have good enough power for the 2.4GHz devices. AUSTRALIA (AU), CHRISTMAS ISLAND (CX) and KIRIBATI (KI): Max TX Power 2.4GHz = 200mW (23dBm) Max TX Power 5GHz = 50mW (17.00dBm) (ch.36-64), 63mW (18.00dBm) (ch.100-165) Number of 80MHz channels = 5 AU, CX and KI have five 80MHz channels instead of six, but a higher Max TX Power on the 2.4GHz band than BW, LR, SA, UG and WS so theese three regions might be good for routers without 5GHz band or when the 2.4GHZ and 5GHz band have different SSIDs. In wich case 2.4GHz Transmit Power can be set up to 200mW (0) if legal. The firmware for some routers have a bug that prevents it from setting some regions (ASUS RT-AC66U is one of them). This in turn will often lead to missing channels and lower Max TX Power since the active region will be the last working one. So when the settings have been saved, go to Tools – System Commands and execute the following two commands: wl -i eth1 country wl -i eth2 country This will show the currently active region. If the active region is not the one previously set in Wireless Settings the firmware is affected by the bug. In that case use the workaround described below. This example will use SAMOA (WS) as the region. 1. setup the wireless settings as usual in Wireless Settings and Save. 2. Go to Administration – Scripts and on the Init tab add the following: wl -i eth1 country WS wl -i eth2 country WS 3. Reboot the router 4. Check the active region as described above, it should now be SAMOA (WS). If a region change is wanted after the workaround, remember to delete the lines from Administration – Scripts -Init tab and reboot the router first. The only country that I could find where you would be in vioalation by using BOTSWANA (BW), LIBERIA (LR), SAUDI ARABIA (SA), UGANDA (UG) and SAMOA (WS) at TX Power 0 would be Austria (if that's really the case anymore), maybe there's more but I couldn't find any. By using AUSTRALIA (AU), CHRISTMAS ISLAND (CX) and KIRIBATI (KI) at TX Power 0 for the 2.4GHz band on the other hand would be in violation in many countries. So check the legal power for your area first. Edit: Well it would also be a good idea to check if the selected channels are legal in your area. Countries seems to have added more channels since the wireless driver in Tomato was released in 2014. I know Sweden now allows ch.149-165, and since August this year UK have added ch.144 and 149-165.