The spare/replacement Battery for the Insta360 ONE X2 camera is the same 1630mAh battery included with the camera. It comes with a battery case so it can be kept safely in your bag until it's ready for use.
Chemistry ... Lithium-Ion Polymer
Capacity ... 1630 mAh
Watt Hours ... 6.27
Output Voltage ... 3.85 V
Charging Voltage ... 4.4 V
Operating Temperature ... -4 to 104°F / -20 to 40°C