The new CastDock X2 has a dock that allows you to install a Chromecast Audio unit right into the top of speaker.
Back in the day there used to be lots of speaker docks for iPods and iPhones. Now we get Grace Digital's CastDock X2 ($150), a speaker dock for Google's highly-rated Chromecast Audio Wi-Fi streaming device.
I've been playing around with it for the last few days and it certainly is an elegant solution for integrating a Chromecast Audio unit -- sold separately for $30 -- right into a speaker (you usually have to attach it to an audio input and have it sit outside the speaker).
What's nice is that the dock has a Micro-USB connector that provides power to the Chromecast Audio and an optical audio cable creates a digital connection. However, I should note that this isn't a portable speaker with a built-in rechargeable battery. Rather, it has to be plugged in.
As for the sound, it's decent but not exceptionally good for a $150 speaker (it plays loud and has some kick to its bass -- it's just not the most well-defined bass).
Bestbuy.com does have it on sale for $100 for Father's Day, and that's what I felt the speaker was worth -- and least from a sound and build-quality standpoint.
The WiFi connection is supposed to provide higher-quality sound but in a speaker this compact, you don't get much of a performance bump over Bluetooth. And weirdly, the speaker doesn't seem to offer a Bluetooth connection, which means you have to buy a Chromecast Audio to wirelessly stream music to it.
According to Grace Digital, here are the key features incorporated into the CastDock X2 and Chromecast Audio (sold separately):
CastDock X2's specifications: