The Samsung Gravity Smart is also known as Samsung SGH-T589, Samsung Gravity Touch 2, Samsung Smart, Samsung GT2 For T-Mobile. It uses a rechargeable li-ion battery.

Samsung Gravity Smart Battery Specs.
Type: Li-Ion
Voltage: 3.7V
Capacity: 1500mAh
Replace Code: EB484659VA
Compatible with Samsung Gravity Smart, Samsung SGH-T589, Samsung Gravity Touch 2, Samsung Smart, Samsung GT2