Include: 2 wheels, 2 motors, 2 encoder kit, screws
Encoder type: 8-pole neodymium magnet and hall-effect sensor
Encoder output: Open drain with short circuit protection
Encoder voltage: 3V – 24V with reverse polarity protection
Encoder resolution: 8 state changes / revolution when mounted on the output shaft 948 state changes / revolution when mounted on the motor shaft
Motor voltage: 3V – 6V
No load current: 200mA
Stall Current: 3A @ 6V 1.5A @ 3V
Gearbox ratio: 118.5:1
Wheel Speed: 135rpm @6V unloaded
http://letsmakerobots.com/node/38636