Waters SYNAPT G2 Operator's, Overview And Maintenance Manual page 59

23. Fit the end cover and gasket to the probe assembly.
Nebulizer adjuster knob
24. Using the combined 2.5-mm Allen wrench, fit and tighten the 3 screws
that retain the end cover.
Gasket
End cover
Installing the ESI small bore capillary option
End-cover retaining screws
3-13