Am sure there are tons of comments on matt box.
I have six different mattbox and don't like any of them. Using a WA some of them are not wide enough and the side is visible in the frame.
So, I am building a very wide one and if am successfull it may even have a Cokin P-mount built in or a 4x5 filter option. Am not sure what it will have until I put one together.
The problem is that I needed a vacuum forming machine for the mattbox. So I built one. It only took a month and should be finishing the mold soon. Then, see how my design works out.
I'll keep you guys posted with pictures and video if you're interested.