This is the SparkFun Hobby Motor with a 6mm, 10 tooth, gear to make your basic projects a little simpler to manage. It works well for basic things like making a fan or spinning something pretty fast without much resistance.
The motor has a normal operating voltage range of 1.0 to 3.0VDC but can handle a max load of up to 12VDC and a no load speed of 6600±10% RPM (@1.0V DC, 110mA). More information is available in the spec sheet linked below.