Brand: Twinmask - Model: MT-90 - Color: Yellow - Quantity: 1 - GPS Chip: SiRF-Star III GPS - Network: GSM / GPRS - Frequency range: 1575.42MHz - GSM/GPRS Module: SIM 900 (four-frequency 850 / 900 / 1800 / 1900 MHz) - GPS Sensitivity: -159 dBm - GPS Accuracy: 15 meter - Warm start time: 35 seconds - Cold start time: 37 seconds - Hot start time: 1 second - Antenna: Built-in - Maps included: Google map - Screen size: No - Screen format: No - PC interface supported: USB 2.0 - Operation temperature: -20 centigrade ~ 55 centigrade - Humidity: 5% to 95% Non-condensing - Altitude limit: 18000 Meters - Velocity limit: 514 Meters / second - Memory: 2GB - Memory Card Type: TF - Max Extended Capacity: 2GB - Battery Type: Rechargeable 750mAh / 3.7V - Battery Standby: 120 Hours - GPS System Features: Small size with buckle on the back convenient to carry; Waterproof rate IP67; Support setting several instructions at a same time; Support setting a SMS center; Support setting 5 authorized cell phone numbers; Power saving mode; Geo-fencing alarm; Support Data logger using Micro SD card