The RearSentry system is an economical accessory for industrial and commercial vehicles that uses microwave technology to alert drivers to objects up to 12 feet behind the vehicle. It eliminates hazardous blind spots and allows for safer and easier backing. It automatically resets when the object is no longer in the area. No maintenance is required, and installation is easy. Rostra Precision Controls Inc. 800-782-3379. www.rostra.com.