Fair warning - I invested years ago, it was a kickstarter or some such, and the very early prototype was a bit clunky and had issues. It *appears* they've addressed all of those, and then some. But a few years is forever, and I have *not* found a good alternative that is: standalone, BLE, secure, supports fido2 and webauthn, and open source. I'd have already pulled the trigger if it was a bit cheaper or had a domestic supplier. I probably still will, come payday.