The valve is constructed so that {TAIL ~ liquid} can be introduced to or removed from {HEAD ~ the bladder}  
The valve is constructed so that { TAIL ~ liquid } can be introduced to or removed from { HEAD ~ the bladder }
OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH