It's a nice 5-AA battery holder, with 5" leads and a 2.1mm DC barrel plug.
400 Tie-points with power rails included. And half sized! It's convenient for small prototyping projects!
Use this 60cm/24" sensor cable to plug in your Phidgets sensor to the Interface Kit 8/8/8.
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.