IWC Schaffhausen SPITFIRE MARK XVI Mode D'emploi page 20

Functions of the crown
X
Normal position
This watch has a screw-in crown. The screw-in connec-
tion (normal position, position X) prevents unintentional
adjustment of the time or the date, and the watch case
has double protection against penetrating water. To
release the secure crown, unscrew it by rotating it to the
left, where it automatically assumes position 0, the
winding position. By depressing the crown in position X
and rotating it to the right at the same time, it is screwed
down firmly again and secured.
0 1 2
X Normal position
(screwed in)
0 Winding position
1 Date setting position
2 Time setting