G'day James,

They have a size adjustment toggle at the back, so I'd suggest getting a Large size, then toggling it in as tight as you need. The Medium will likely be a bit too small and might give you a headache if you're wearing it all day.

G'day Mia,

For some reason, Jack Jumper don't put cm measurements on a lot of their hats, unfortunately. The smallest size we have available is the Small which fits my head almost perfectly, perhaps a smidge tight (my head measures approx 56cm). I'd definitely go with the XS for your children but they also may find the XS a little big. 

For some reason Jack Jumper don't put cm measurements on a lot of their hats sorry, Kev. For a 56cm melon though, I'd go with a medium size Legionaire's hat.

It's a green, Bob. The images give it a somewhat grey appearance but the colour is actually an olive green. 

G'day Steven,

With a 54cm circumference, I'd probably suggest the Small Jack Jumper Legionnaire's Hat for you.