Revive your AT&T Netgear with this 2400 mAh, Lithium Ion Battery. You get a New Battery for your NetGear AC778AT-100NAS Mobile WiFi Hotspot, Special Installation Tools, and an easy to follow Battery installation Video. You also get a full ONE YEAR Money Back Guarantee on the battery when you purchase from us! Please note that while the replacement battery has less mAh capacity than your original battery, it works in your NetGear AC778AT-100NAS device.