The VIAVI (formerly JDSU) E20LIPO Rechargeable 7.4V Lithium Polymer Battery (4800mAh, 35.52Wh) is an accessory for the T-BERD/MTS-2000 Handheld Modular Test Set. It provides up to 9 hours of operation as per Telcordia GR-196-CORE. Operating temperature is from -4°F to 122°F (-20°C to 50°C). Store the unit at the temperature from -4°F to 140°F (-20°C to 60°C).