Includes!
You'll need 6 AA batteries, a CR1220 coin cell, some wire and soldering tools to assemble the project.
For more information, including libraries, schematics and examples see the data logger shield webpage
Tested works with Arduino Uno, Leonardo, Zero, Due, and Mega R3 or later.
Note: As of September 6th, 2016 this product no longer contains a coin cell battery. You can pick one up here