A hydration sensor or sensing element configured to measure {HEAD ~ the hydration level} of {TAIL ~ a user} is disclosed 
A hydration sensor or sensing element configured to measure { HEAD ~ the hydration level } of { TAIL ~ a user } is disclosed
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH