This Ultrasonic scanner is made by Devantech that has a longer range than the SRF04.
This great sonar ranger from Devantech offers an amazing wide range from 3cm to 6m. Unlike the SRF04, the SRF08 is interfaced using the IIC/I2C bus. There is an additional photocell sensor on the front of this detector.
The HD2 tracked platform is a large, heavy duty tracked robot with the power to pull a truck and climb stairs. A wealth of internal space allows for batteries, controls and an optional computer. Customized version of item TP-200-001.
900 MHz 3 dBi Rubber Duck Antenna - RP-SMA Plug Connector