Podofo Mini GPS Tracker Tracking Device Travel Portable Keychain Locator Pathfinding Motorcycle Vehicle Sport Handheld Keychain Built-in GPS Module, it's the best choice to climb the mountain or forests! However most of other GPS trackers need to install a SIM card, which will be no signal in mountain. Kindly noted that use it in opean areas without obstacle, it takes a whiletime to get the satellite signal. Specifications: Receiver: L1Type, C/A Code Capture channel: 51 Tracking channel: 14 Maximum update frequency: 10 Hz Display: pixel height * width 128 x 64 dot matrix Size: 65mmx 52mmx 21mm Weight: 39.6g (With the battery) Memory: 512KB Key: 3 function keys Location: 10m (Support the difference correction system area up to 2 meters) Speed: 0.1m/s The initial positioning time: Hot start: About 5 seconds Warm start: About 40 seconds Cold start: About 2 Minutes Sensitivity:-161dBm tracking/ -157dBm re capture/ -148dBm capture Data protocol: NMEA-0183 v3.01 The power supply voltage: USB DC 5 V / 3.7 V 390 Ma the built-in lithium battery The operation time: approximately 6 hours Power waste: Capture: about 70 Ma Continuous tracking: about 30 Ma Storage temperature: -30°C to +85°C Working temperature: -20°C to +75°C Humidity: Up to 80% non-condensing Range of use: This product only work under outdoor sky open areas around elevation 15 ° no building cases to receive satellite signals! Package includes: 1 x Mini tracker 1 x USB cable 1 x Instructions