I ordered two of these and both are unreliable. The batteries fit too tightly and when the lid is closed they can lose contact with the contact pads inside. They can be made to work, but who wants to fiddle with it every time you install batteries.

This case is kinda dumb. There's no proper way to mount it since the lid is on one side and the switch is on the opposite site. And there are no holes to mount it anyway. If the lid and switch were on the same side, at least it could be glued sensibly.

Yep, these are not too great, as mentioned they are unreliable, loose contact, too tight, hard to open without the aid of a tool.

So, this is kind of awkward to mount, but I've found at least one good way to mount it. Say you are mounting it inside a project box. First drill a hole in the side of the box, bigger that the switch. Now, you can use double-sided foam tape to attach the battery holder to the project box, such that the switch is under the hole. Now the switch is accessible from outside and you can get to the battery compartment from inside. Also, I've found that the lid doesn't really fit on the box with batteries installed unless you really jam it, or break off the tab on the lid.

I have a video explaining how to fix the problems with this battery pack being to tight to hold the batteries here: http://www.youtube.com/watch?v=R9KC2-_whjw