Conveniently, although not necessarily, this will be a position in which the reservoir is at least partially inverted, with {HEAD ~ the outlet opening} thereof in {TAIL ~ a lowermost position} 
Conveniently , although not necessarily , this will be a position in which the reservoir is at least partially inverted , with { HEAD ~ the outlet opening } thereof in { TAIL ~ a lowermost position }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL