The sealed ATU-620™ high-value tracking unit from CalAmp features a small size, superior GPS performance and replaceable AA Alkaline batteries. The ATU-620™ is a complete asset tracking and communications device incorporating next-generation, super-sensitive GPS technology on GSM/GPRS, CDMA 1xRTT and HSPA cellular networks for installation inside any mobile asset. Superior internal antennas for both cellular and GPS eliminate the need for wired antennas and make the ATU 620™ mountable virtually anywhere for easy, inexpensive installations. Messages are transported across the cellular network using enhanced SMS or UDP messaging providing a reliable communications link between the device and your application servers. The ATU-620™ is designed to dramatically reduce cost and size while significantly improving field reliability.