Have my old trusty Cavision bellows matte box w/ rods connection bracket up for grabs. Two slots for 4x4 filters, one stage rotates.

I ended up shortening the two small rods that extend the bellows (as seen in pic) since the longer rods were hitting my support for my DSLR when I used the 7D/GH2 with the camera. Should not pose a problem as it has worked perfectly with my FS100 and lens package from 18mm-150mm.

The rotating stage sticks a bit, but you just have to make sure the 4x4 filter is seated correctly. I'm also missing a thumb screw that cinches the MB to the rails, though that is easily replaced at a hard ware store...and I never bothered since the MB stays where it is on my rails without sliding.

I'll also throw in for free a Schneider 4x4 circular tru pol. It's got a small crack running through it from my dumb ass dropping it on set a week ago. We still ended up shooting with it out of necessity, and the crack did not appear on any of the footage. I replaced it with a new one, and it just seems wrong to throw this out. They go for $245 at the moment as well.

$275