I built some of these last summer when I found SHB in my first hive. Of course I found that I wanted / needed to make some changes. I finally got around to knocking off some new and improved ones on this (extremely) rainy afternoon.
I use 8 frame equipment and as you can see a disposable aluminum turkey pan is just about the perfect size for the oil pan - a little deep, but at least it isn't hard to keep from spilling it, and the price is right.
In the old version I had to take out the oil pan to use a sticky board (1/4" blue insulation board with oil on it) for mite counts. In this one I also put a grove under the bottom to store the sticky board when it isn't in use.
The access door on this one is recessed and is tighter to (hopefully) keep ants from taking up residence in there. Also, I wanted to have some screened vent holes on this version which you can see. I didn't really give to much thought about how to close those up when it gets cold. I guess I'll work that out for ver 3.0
I think that small, well guarded, single entrances should be useful to combat SHB.
As you can see from this inside view that for a beetle to get in (or a beetle larva to get out) it will have to make its way through the tunnel formed by the entrance reducer over the oil pit of death. I haven't tried this yet, but it seems like it should make life harder on the little buggers. also notice in this shot that the way the SBB is made there isn't any rim around the perimeter of the floor like on most, so more likely that the beetles will tumble in.
BTW, the ones that I made last year were basically the same idea, and they worked quite well to control the SHB. Other than the new entrance reducer design all of the changes in this one are mostly just for convenience.