Approximately how long do the GPS Smart Pendant batteries last? Are they rechargeable?

The GPS Smart Pendant uses a rechargeable, non-removable lithium ion battery that will operate for 1-3 days, depending on how active the wearer is. The pendant “goes to sleep” to conserve energy when stationary, and “wakes up” when moved. The device is water resistant and can be worn in the shower, but it is recommended that it not be submerged for long amounts of time (swimming, bathing, etc.)