Thought since a discussion was going on about these, I'd show the instruction sheet and the pics of mine when I installed them, along with some comments.
I like them!

They latch securely, open easily, and are, in general, a nice option to the POS snap doors that come on the bike. Certainly, if you stuff them to the point of things wanting to bulge out of the box, they are not a solution, but for normal use, I don't see a problem with them coming open accidently and stuff falling out, especially if you put heavier things on the bottom and leave the top for things like sunglasses, cloths, etc.
Tools you'll need: 5/32" allen wrench or allen socket for the button head screws; 7/16" open end wrench; 10mm open end wrench; a #0 Phillips Head screwdriver; Sidecutters; Blue Loctite. The instructions say to remove the box assembly, but you don't have to do this, just cut the plastic male end of the snaps off with the sidecutter and knock out the remaining backside with a phillips or round blunt end punch. Easy as pie...effortless, and you'd have to do something stupid to mess anything up. Remove remnants from the boxes. When installing the bottom button head screws and locknuts, just run the screw in enough to where you feel the end of the screw with your fingertip as it comes through the locknut...Flush is good. Too tight, and it will deform the bottom of the cover where the screw head sits. The rest is pretty straighforward.
Here's the directions: