The Lithium555 by Flexopower is shipped and delivered in a locked state. This means, there is no AC and DC output, even with the buttons pressed. To activate the AC and DC output, you first need to unlock: press AC and DC buttons for 3 seconds until "OPN" appears in the display. Only then can the AC and DC outputs be switched on. To lock theLithium555 again, press both buttons again for 3 seconds until "LOC" shows.
This is also a great feature if the Lithium555 put into storage or left unsupervised around children and impaired persons.
Here is a video visualizing the process: