New $268, selling for $150 plus shipping.

Used in an experiment for a few days recently. Works to send Dolby Atmos / Vision and most other audio and video signals to two separate installations, e.g. a soundbar and a receiver simultaneously. I used an eArc soundbar and an eArc receiver to playback Dolby Atmos audio simultaneously, but it has many other potential usages. 

From the supplier:

ZONE2-PRO 8k eARC Audio Processor (thenaudio.com)

ANOTHER WORLDS FIRST: eARC INTO DUAL OUTPUT FOR TWO AUDIO SYSTEMS

You will be able to continue using your perfectly capable home theater sound system / sound bar / headphones supporting all the latest audio formats from your TV using eARC. Receive audio from TV via the eARC channel and converts the incoming audio formats suitable for the existing sound system that has no eARC support. You will be able to continue getting audio from the TV up to the maximum capability of your current sound system.

HDMI outputs are capable of up to high bit rate audio formats such as Dolby MAT Atmos, DTS-X, DTS-IMAX, TrueHD, DTS-MA.

The separate optical output is capable of up to 192kHz encoded bitstreams, such as DD+ or DD+ Atmos. Optical output also supports PCM stereo signals.

• HDMI Audio and eARC transmitter output ports
• Two HDMI 2.1 48Gbps FRL6 inputs with CEC control
• TRACKSYNC volume control between displays
• Video support: All formats up to 48Gbps FRL6 from any HDMI source, such as 4k120 444 10/12bit VRR, 8k60, and others
• Audio support: All formats, such as lossless MAT Atmos, TrueHD, DTS:X IMAX, DTS-MA, PCM 7.1 192kHz 24bit, and others
  • TV may limit supported formats depending on its eARC implementation. Consult the TV manual for supported modes.
• Video encryption support: All levels of any encryption
• Perfect PassThrough: Video content is never decoded and re-encoded. The bit accuracy is maintained even for the most demanding formats (cable limited)
  • Any video feature is supported (VRR / FRL / ALLM / .. )
• Supports CEC switching and command passthrough using the TV remote and the source remotes.
  • Use AppleTV / Roku / Xbox / other remote controllers to control the volume level, mute and source switching.