The sensing element can be coupled to a bottle of fluid, or {HEAD ~ a carrier} with {TAIL ~ a timer} 
with
The sensing element can be coupled to a bottle of fluid , or { HEAD ~ a carrier } with { TAIL ~ a timer }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL