I bought a pack of 4, but I only used 2, so I'm selling the rest. They haven't been paired. Purchased in 2025. Can be used as a tracker (location tracking) from Android's "Find Hub". The battery is a CR2032 (button battery), and it's replaceable. The battery lasts about 6 months to a year, depending on usage. --- - Brand: MiLi - Model Name: MiTag - Color: Black - Compatibility: Compatible with Android devices Thank you for looking.