Marey TANK10L Mini Tank, 2.5 Gallon, White Highly efficient. The 10 liter mini tank will always instant hot water It is perfect to be installed under the sink It saves space Perfect for remote places or places at home far from the tankless heater Various applications: can be used for a Small supply of hot water under the sink or also to provide hot water on the shower until hot water comes from the tankless heater This is an aftermarket of generic part