Mouser/DigiKey part number for female "stacking" headers? Adafruit has this wonderful product: http://www.adafruit.com/products/85



What are these actually called? I've looked all over the place in Mouser and DigiKey and can't find them (now, granted, it's impossible to find anything in DigiKey since they discontinued their printed catalog, but I'm digressing...)

They are great for putting other things that are on breakout boards on a tightly-packed breadboard and still be able to attach probes.

Also, sometimes, the board you are trying to attach is this:

As you can see, there is a dip switch blocking the 8-pin header. This is fine for its final resting place (on a board with a socket), but putting it on a breadboard is a bit of a pain. I have quite a few of those, so even though the aforementioned adafruit part is pretty cheap and I could get a bunch, I'd rather know what the real part is called so I can get the sizes I need.

PS: In case you are wondering, and you like old-style nixie tubes, that's http://www.tayloredge.com/storefront/SmartNixie/DataSheets/Datasheet_SmartNixie.pdf.)
They're actually called "Wire-Wrap Headers" and they pre-date the Arduino probably by at least 50 years or so.

They used to be used to create circuits between chips and components by wrapping wire around the pins and routing it to other connectors:



They have since been adopted as stackable headers on boards like the Arduino shields.

Being such old technology not many people make them any more, though thanks to their popularity on things like the Arduino they are starting to appear more and more from normal electronics supply companies.