The same unit as "Pluggable USB 2.0 4 Port Hub and BC 1.1 fast charger 2.5 Amp power supply" ... see here: http: / / elinux.org/RPi_Powered_USB_Hubs -> Pluggable 4 Port Hub with Battery Charging 1.1 Support USB2 HUB4BC
Identical and cheaper ...) only one power supply for all, no "back power", hard disk running at