Implantable devices like glucose monitors can be placed under the skin with a simple incision and linked via Bluetooth.

“I think there are people walking around nowadays with glucose monitoring devices, like Levels-- which I've used and it was very informative for me, actually, as a kind of an experiment. Gave me a lot of interesting insights about my blood sugar regulation, how it reacts to different foods, et cetera. Well, you can implant a tactile device below the skin with a simple incision. Actually, one of the neurosurgeons at Neuralink I know well because he came up at some point through my laboratory and was at Stanford, and he actually has put in a radio receiver in his hand, and his wife has it too. And he can open locks of his house and things like that, so he's been doing--”