{HEAD ~ The sensing element} or sensor can be calibrated for a specific user or {TAIL ~ a group} of users 
{ HEAD ~ The sensing element } or sensor can be calibrated for a specific user or { TAIL ~ a group } of users
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH