Containers 11 and 12 may be {HEAD ~ a common unit} separated by a liquid tight partition 16 and provided with {TAIL ~ a hinged cover} 17 
Containers 11 and 12 may be { HEAD ~ a common unit } separated by a liquid tight partition 16 and provided with { TAIL ~ a hinged cover } 17
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH