Tracking Key 3100 EXT GPS Tracking System with EXTERNAL Antenna and Past-Track Software for Windows CD -- Tracks up to 5 weeks of Driving Time (1 hr per day of driving time) -- Weather-Resistant ABS Plastic Case with powerful integrated Magnetic Mount can be conveniently located on any vehicle -- 4.2 x 3.4 x 1.7 inches (including the built in magnetic mount) -- 4 Standard AAA Alkaline batteries power the Tracking Key for up to 5 weeks (with an average of 1 hour per day driving time; even longer if lithium batteries are used) -- Tracking Key automatically enters battery conserving Sleep Mode after 3.5 minutes of no movement -- Accurately tracks locations with 2.5 meter accuracy -- Included Past-Track Windows Software CD installs on PC and displays data as text, street map, or automatically exports to Google Earth (separate free software download from Google site) -- Absolutely No Ongoing Monthly Service Fee; US DOD Satellite Signals are available for free anywhere around the globe -- Gain Peace of Mind knowing where your vehicles have been, how long they stopped, and how fast they travelled -- It is buyers sole responsibility to know and understand laws about tracking devices in buyers area. This GPS Vehicle Tracking Unit is a great way to track a vehicle. When you need to find out where the vehicle traveled, you simply download the data. And NO MONTHLY FEES! This GPS Vehicle Tracking Unit is a great way to track a vehicle. When you need to find out where the vehicle traveled, you simply download the data. And NO MONTHLY FEES!