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Adafruit Industries Mini Solderless Breadboard$0.95
Add a micro-slice standard solderless breadboard to your Perma-Proto or other perf-board. This 2x8 point solder-less breadboard is a good way to add some solderless prototyping space if you just need to have a couple points. Comes with one 29mm x 8mm x 8mm piece of solder-less breadboard.
There are two white posts on the bottom for PCB positioning.