Bosch Ariston GL4S (Ariston GL4) Electric Mini-Tank Water Heater - Installing an Ariston electric mini-tank water heater under the sink puts hot water right where you need it -- at the point of use. Easy installation. Simply tap into the cold water line and install the water heater directly at the sink. Plugs directly into a standard 120 volt outlet. And when you want to eliminate the wait for hot water but need more volume, install the Ariston water heater in-line with a larger hot water source. The Bosch Ariston GL4S (Ariston GL4) keeps 4 gallons of hot water ready to go and draws only 12.5AMPS. A Pressure relief valve is included. The Bosch Ariston GL4S is a replacement for the Ariston GL4, but please note that the GL4S is 13.5" deep while the Ariston GL4 was only 12.25" deep.The new Ariston GL4S has many new improvements over the older Ariston GL4. The Ariston GL4 has a new temperature adjustment knob on the front of the unit to raise and lower the temperature from 65 Deg F to 145 Deg F while on the older Ariston GL4 you would have had to remove the blue oval cover to access the temperature control knob.The Ariston GL4S also has a new improved thermostat that features a new sensing probe that is attached to the thermostat and inserts into the cavity of the new element so the heater can adjust temperatures quicker and maintain a more consistent heat.