Waterproof ultrasonic distance sensor. This sensor can be used for collision detection in your project.
Ultrasonic Module HC-SR04 Distance Measuring Transducer Sensor.
This is the SRF05 Ultrasonic ranger made by Devantech. The Ultrasonic detector can detect from ~4 inches to ~13 feet.
Ready to ship All-Terrain 4WD Robot Platform. This robot has 122RPM motors, and can handle most terrain with ease! A rollcage offers additional protection!
A ready to ship custom prebuilt All-Terrain 6WD robotic platform. It features 10" pneumatic tires and IG52 136RPM gear motors. RC controller, battery, and charger included.