Amazon.com: Made For Amazon, Battery Base in Black, for Echo (4th generation). Not compatible with previous generations of Echo or Echo Dot (1st Gen, 2nd Gen, or 3rd Gen). : Everything Else
Amazon Echo Dot (3rd Gen) - Charcoal in the Smart Speakers & Displays department at Lowes.com
The History of All the Amazon Echo Devices | Digital Trends
Amazon Echo (2nd Gen) Smart Speaker with Alexa
Amazon Echo Dot 3rd Generation Review (3rd Gen. vs. 2nd vs. 1st)
Amazon.com: Fremo Evo Plus Battery Base for Amazon Echo Dot 2nd Generation (Black) : Everything Else
Amazon Echo (2nd gen) review: smaller and cheaper, but mostly the same - The Verge