At least one, and preferably both of the aforesaid half shells are closed by {TAIL ~ associated sealing sheets} {HEAD ~ the connection} of which on the facing surfaces leads to the connection of the two half shells 
At least one , and preferably both of the aforesaid half shells are closed by { TAIL ~ associated sealing sheets } { HEAD ~ the connection } of which on the facing surfaces leads to the connection of the two half shells
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH