The Linksys WUSB6100M Max-Stream AC600 MU-MIMO USB Adapter  is the world’s first MU-MIMO enabled adapter. It was launched in Singapore on 1st August 2016 and is currently retailing for S$129.
The WUSB6100M adapter allows you to connect your PC to a wireless-AC network as well as a MU-MIMO router.
Unfortunately, you can’t use this adapter with a Mac because there is no software or driver for it on the Mac.
It supports 802.11ac Wave 2. 802.11ac Wave 2 is an addition to the original 802.11ac wireless specification that utilizes MU-MIMO technology.
The reason why there is an AC600 in the name is because it supports dual-band AC Wi-Fi speeds up to 600Mbps. 433Mbps on AC and 150Mbps on N.
You can read more about MU-MIMO on my Linksys EA8500 Max-Stream AC2600 MU-MIMO Gigabit Router Review  which I did last year.
I also have with me the Linksys Max-Stream AC1900+ MU-MIMO Range Extender (RE7000)  and the Linksys Max-Stream AC5400 MU-MIMO Gigabit Router (EA9500) . So stay tuned!