Wall mounted electric water heater.
The heater is connected via the MEM fused connection unit as can be seen in the photo directly to the right of the heater.
Cold water enters the heater via the black valve underneath. This pushes water upwards, and the hot water flows into an open pipe inside the heater, which goes down inside the casing and exits via the chrome plated spout.
The open spout also serves as a vent, so in the event of steam or overheating, hot water can exit via the spout. This also means the spout drips as the water heats up and expands.
A crude thermostat is located in the base of the appliance. Crude, as although it has various temperatures marked on it, the device is grossly inaccurate.