Flexfitmens Multicam Trucker Cap Hat, Multicam, One Size US

What are the measurements for the hat listed as 'one size'?

Does this hat ship in a box so it doesn’t get smashed? Thanks

is the mesh part rigid like normal trucker hats? as in, if my head doesn't touch the top back of the hat, will it still keep its shape?

How do you order the size you want? No size selection options?