Look like it's advertised on their leaflet/instore only. Not advertised online.
Normally £11.89 each. 2 for £18 offer. Bargain! So £9 each.
2-way switched socket with 3.1A shared between 2 USB sockets (so it'll charge an iPad, unlike earlier weaker 2.1A ones which struggle).
It's 20mm deep so it'll fit a standard 25mm back box & has SMART USB so will switch to standby mode when device is fully charged (so not to overcharge) & will auto detect a USB device has been plugged in so will adjust charging pattern.