Heavy duty robot wheel with traction lug Tiller tread. It does not have a bearing. Size: 3.5-4. It's 10.5 inches in diameter, 3.5" inches wide. Its Pneumatic with a 4 bolt pattern so you can easily mount it to a flanged hub.
This is a 4WD IG42 single bearing platform that is setup for outdoor navigation/positioning. A full array of sensor options including an IMU, motor encoders, and a Garmin 18x GPS that can provide position feedback with up to 3 meter accuracy.