Brim to Brim / Inside Head. 2" (5cm) / 1" (2.5cm), 2.75" (7cm) / 1.25" (3cm), 4" (10cm) / 1.5" (4cm, 5" (13cm) / 1.75" (4.5cm), 5.25" (13.5cm) / 2.25" (6cm), 6.25" (16cm) / 2.5" (6.5cm).