Powerful Extended GPS Tracker Battery & Monster Magnetic Case for GL200 and GL300 Tracking Devices (Including GL300V GL300VC and STI_GL300) POWERFUL BATTERY. Add up to 3 months of recharge-free tracking life to your GPS tracking device with this 3-cell, 3.7V, 7.8Ah battery pack. WATERPROOF. Magnetic case secures tightly over a gasket that runs the perimeter of the lid and body. SECURE. The enclosure is equipped with 2 ultra-strong neodymium magnets that securely adhere to any ferrous steel or iron surface. EASY INSTALLATION. We've eliminated the need for that annoying patch cable - the battery plugs directly into the charging port of the tracker and it all fits neatly inside the case. Exterior Dimensions: 4.9 x 3.5 x 1.6 Inches (Magnet: 0.38 Inches); Interior Dimensions: 4.4 x 2.9 x 1.7 Inches