1"x1" square funnel trap. Pretty big not sure of dimensions. 1/4" screen funnel construction. These big traps are bulky. But you get them in the right place early season ice before winter die-off and they will hold a lot of rats. Get 3 or 4 working good and that's about all the skinning I care to do, maybe 10-12 /trap/check. You can make them round too.
Scratching up a few spring rats ( low population post winter kill) they are good for wide open areas and culverts.
Edit: Counting squares this one looks to be about 36x12x12