Tiger PVW-B30U Stainless Steel Vacuum Electric Water Dispenser, 3-Liter 2 way styles for dispenser: Electric and air pump without using electricity Choices of Energy saving modes: VE mode & Energy Saving Mode VE Mode is when the water boils, heater shuts off automatically and uses Stainless Steel Vacuum Insulation to keep warm Energy Saving Mode applies after 2 houes not in use; It reduces approximately 9F from regualr setting temperature Auto lock system after dispensing for safety