XTAR EDC flashlight WK41 Sirius AA 1.Battery type recognition, different battery provides different output 2.Automatically shift down: When use lithium batteries, voltage is below 2.75V, WK41 turns off automatically. 3. High efficiency constant current driver circuit 4.Click the switch to change between lighting modes, Double click the switch to access and change between the Hidden modes. In either Hidden mode, pressing the switch once changes to Low mode. 5. Reverse-polarity protection to prevent damage from incorrect battery insertion