'Working Based on existing GSM/GPRS network and GPS satellites, this product can locate and monitor any remote targets by SMS, app and Internet. It adopts the most advanced technology of GPS and AGPS Dual positioning. Dims: 90 mm x 72 mm x 22 mm (3.5 "* 2.8" * 0.8) Weight: 168 g network: GSM/GPRS Band: 850/900/1800/1900MHz GPS Sensitivity: 159dBm GPS Accuracy: 5 M Wall Charger: 110 - 220 V Input/5 V - 1 A Output Battery: Chargeable 3.7 V 5000 mAh Li-ion Battery Stand by: 90days time to first fix: Cold status 45s/Warm status 35s/Hot status 1s Storage Temp.: -40 °C to + 85 °C Operation Temp: -20 °C to + 55 °C Humi dity: 5% -- 95% non condensing