It's a nice 5-AA battery holder, with 5" leads and a 2.1mm DC barrel plug.
Need to add more voltage to your regular 4AA battery pack? Parallax has come up with this ingenious plug in module that adds a 5th module to your AA quad-pack holder.
This is a coin cell holder for the common CR2032 type battery. The holder has a neat pop-in, pop-out feature that makes changing the battery easy.
Need a tidy DC-to-DC converter? This SparkFun breakout board offers 6 amperes of conversion, taking any DC voltage between 4.5-14VDC, and turning it to a selectable voltage between 0.59 and 5.5VDC.
These are very slim, extremely light weight batteries based on the new Polymer Lithium Ion chemistry.
Switchable Voltage Divider is a voltage divider with switches. The switches can be used to control which resistors are used in the voltage divider.
The DE-SWADJ is the adjustable version of the "SW0XX" step-down voltage regulators. Using the same form-factor as a standard 78LMXX style regulator, it is a much better way to give regulated voltage to your project.
The DE-SWADJ 3 is a larger version of the DE-SWADJ adjustable step down voltage regulator, and is designed to be stronger, faster and better.