Description Overview Two fourth passage gill boxes for working pure wool 100%. Machine 1 NSC Schlumberger fourth passage gill, model GV.11. Year 1993, serial number 28345. Delivery of 2 slivers into 2 cans, diameter 700 x 1200 mm. Machine 2 NSC Schlumberger fourth passage gill, model GV.20. Year 1997, serial number 29787. Delivery of 4 slivers into 2 cans, diameter 700 x 1200 mm.