You sell a nice USB A to power jack https://www.adafruit.com/products/988
and yet the Raspberry Pi takes a micro-B USB plug.
this requires buying a USB-B to micro-B cable USB cable - A/MicroB - 3ft http://adafruit.com/products/592
to interface to a standard power supply with 2.1mm setup
so ok I do have one of the Sparkfun Hydra cables on my bench but I would much rather have a clean simple rig for packaging a project for field use.

