Toolbox

Toolboxes come in three flavors; Mechanical, Electrical, and Emergency. All of them can be used to store various items, and are fairly heavy so they make decent bludgeoning weapons. Toolboxes have a smaller capacity than Backpacks - both have seven storage slots, but Toolboxes cannot accept larger items like Backpacks can, and backpacks can't hold toolboxes. The internals box in your bag works just as well and you can fit it in your bag, but it's not as good of a weapon.

Gettin' Advanced

For a more detailed guide on individual toolboxes, see:
Emergency Toolbox
Mechanical Toolbox
Electrical Toolbox