final --> for primitives --> value can't change. for non-primitives --> you can't change the reference and point it to another object. Note : It is different from immutability.
Hands down, the Bluetooth speaker with the longest battery life is the Fugoo. It offers up to 40 hours of battery life, nearly twice the battery life of other leading Bluetooth speakers in this category. Given how long its battery lasts, you might even forget that the Fugoo needs to be plugged in to charge.
This item Nixeus ARC 4.0 Ultra-Portable Bluetooth 4.0 Wireless Speaker with aptX, Internal USB Power Bank, Built in Speakerphone, Long Lasting 18 Hour Battery Life (Red)