Here’s a new biometric I know nothing about:
The wristband relies on authenticating identity by matching the overall shape of the user’s heartwave (captured via an electrocardiogram sensor). Unlike other biotech authentication methods—like fingerprint scanning and iris-/facial-recognition tech—the system doesn’t require the user to authenticate every time they want to unlock something. Because it’s a wearable device, the system sustains authentication so long as the wearer keeps the wristband on.
EDITED TO ADD (12/13): A more technical explanation.