[paisawalla]

Their entire product line seems to be "currently unavailable" on Amazon.

[CobrastanJorji]

Looks like they hope to be back in stock late this month. They've got some availability notes on their website: https://www.caldigit.com/an-update-on-ts4-availability/

I imagine they're being hit by the chip shortage that impacted so many other companies. I'm still waiting on a Raspberry Pi, myself.