The Borexino area of the "Hall di Montaggio" (Assembly Hall) at LNGS (external labs). Left to right you can see the PMT assembly and test rooms, the PMT water test tanks, the "TLTC", two of the "Isotanks" for PC transportation as well as the H.d.M. clean room where (among the other things) PMTs and their ancillary parts have been thoroughly cleaned & assembled before being brought underground for installation.