neb: I'd resisted putting up a Timms because of concerns about non-possums getting caught, but you really can't beat them for getting possums and it's set way down in the bush where I've never seen anything go.
And another one in the Timms:

For anyone contemplating getting a possum trap, don't even bother looking at anything else. I've got mine set up with a PIR sensor that pings me if there's movement by the traps down in the bush, useful to know so you don't end up with a several-day-old dead possum festering away. It's also a good safety check for non-possums being around the traps, so far nothing except birds stealing the possum lure.