He Puckdropper:

I use these terminals on my decoder boosters. They are really nice and
easy to trouble shoot: Here is a cheap source:

http://www.goodluckbuy.com/2-pin-screw-terminal-block-connector-5mm-pitch-100-pcs.html

They also have 3 terminal blocks. And they all dovetail together. I
think the photo shows them at a slight angle due the the holes in the
circuit board. It would be worth redrilling a few holes to have them
straight.

Carl.