The USB Charger/Tamper Resistant Outlet provides:
The 2.5 Amp USB outlets on this USB Charger/Tamper Resistant Outlet are optimized for use with certain types of devices such as bluetooths, and cell phones. As a result, the USB outlets may not charge all models of all brands of your mobile devices. If any of your devices will not charge using the USB outlets, use the 15 amp 125V outlet and the AC adapter of your device for charging.
The two USB outlets are designed to charge two devices simultaneously. However, if you plug in two devices to charge simultaneously and their combined power requirements exceed the power capacity of the USB outlets, they will shut down to protect your devices. In that case, try charging each device by itself.