I have mentioned how handy these metal mitre boxes and the micro saws before. It is an essential part of my tool kit. I use it all the time when working on models. The first one I bought was not wide enough to fit a .250″ strip of material in the box. I just found a new version of the mitre box that is wider and longer. I now easily fits .250″ strip easily in the box as you can see above. The dimensions are .410″ wide, .288″ deep and 4.255″ long.
The new box is sold by UMM-USA
UMM is an online supplier of items used by military modeler. This product sells this very handy tool for $16.95 for part number MN048.
I recommend the product to you.