The sensing element can be a disposable element, {HEAD ~ an element} applicable for more than one time use, or {TAIL ~ a re usable element} 
The sensing element can be a disposable element , { HEAD ~ an element } applicable for more than one time use , or { TAIL ~ a re usable element }
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL