The system effectively seals {TAIL ~ the active agent chamber} and isolates it from {HEAD ~ the environment} of use 
The system effectively seals { TAIL ~ the active agent chamber } and isolates it from { HEAD ~ the environment } of use
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH