The number of stitches cast on for each size is the same, the needle size changes.

Gauge/Tension
13 stitches and 18 rows to two square inches on UK No 11 needles (US2.5/3mm), in stocking stitch
12½ stitches and 17 rows to two square inches on UK No 10 needles (US3/3.25mm), in stocking stitch
12 stitches and 16 rows to two square inches on UK No 9 needles (US5/3.75mm), in stocking stitch

Measurements
Headband (slightly stretched)
16, 17, 18 in

Materials
Patons Fiona (all sizes)
Natural 1 X 2 oz ball
Dark blue oddment
Light blue oddment
Red oddment
Yellow oddment
Green oddment
Set of four needles with points at both ends.