The hat is mostly worked in stocking stitch with a wide panel of ribs and cables for embellishment.

Size
(I am unsure about that: According to the pattern notes, the actual hat circumference is bigger than the head it’s supposed to fit. In the picture, however, it appears the hat is worn with negative ease. So there might be a mix-up here.)
To fit 47 / 53 / 56 cm circumference
Actual circumference 50 / 57 / 64 cm
Height 20 / 21.5 / 23 cm

Yarn
2 x 50g balls in 020 Light Grey