Made For Amazon, Battery Base in White, for Echo (4th generation). Not compatible with previous generations of Echo or Echo Dot (1st Gen, 2nd Gen, or 3rd Gen).

Price: $43.99
(as of Aug 30, 2022 21:33:24 UTC – Details)

Certified “Made for Amazon” accessory specially designed to work with Echo (4th Gen). Echo sold separately.
Enjoy your music away from the power outlet with integrated battery lasting up to 5 hours.
Seamlessly attaches to the to the base of Echo (4th Gen) without tools.
Not compatible with previous generations of Echo (1st Gen, 2nd Gen, or 3rd Gen).
Not compatible with any generations of Amazon Echo Dot.