https://www.adafruit.com/products/711

These are standard '130 size' DC hobby motors.

They come with a wider operating range than most toy motors: from 4.5 to 9VDC instead of 1.5-4.5V. This range makes them perfect for controlling with an Adafruit Motor Shield, or with an Arduino where you are more likely to have 5 or 9V available than a high current 3V setting.

They'll fit in most electronics that already have 130-size motors installed and there's two breadboard-friendly wires soldered on already for fast prototyping.

 

Specifications:

    Operating Temperature: -10°C ~ +60°C
    Rated Voltage: 6.0VDC
    Rated Load: 10 g*cm
    No-load Current: 70 mA max
    No-load Speed: 9100 ±1800 rpm
    Loaded Current: 250 mA max
    Loaded Speed: 4500 ±1500 rpm
    Starting Torque: 20 g*cm
    Starting Voltage: 2.0
    Stall Current: 500mA max
    Body Size: 27.5mm x 20mm x 15mm
    Shaft Size: 8mm x 2mm diameter
    Weight: 17.5 grams