Have not seen this standard anywhere, it does not fit on usual suspects, PC mainboards pci-e, pci and it's way too big for any laptos, is it some industrial std or what, label do not give even partial hits. Maybe it's custom made card for Sonos, it's is possible but very expensive. One this interests me, how are they able to keep hackers out and users in, if they would use std computer parts, they be hacked within first 48 hours. Custom parts keeps huzzlers out and customers in because that is the hardest part, maintaining loyal user base that generates steady income and positive cash flow.