{TAIL ~ Commercially available sensors} which determine {HEAD ~ the type} of gas include depleting or non depleting sensors 
{ TAIL ~ Commercially available sensors } which determine { HEAD ~ the type } of gas include depleting or non depleting sensors
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH