The grateful dead licensed out their brand to Mary Jane's Imports for a large number of official products. I estimate this hat's age to be between 20 - 25 years old. This is one neat hat.
It's made of cloth covered foam. Hat is in good condition for it age and use, it has a spot see photos.
It's floppy, so I stuffed it just for the pictures. If you have any questions let me know.