Vintage 1960s Ladies Clover Lane Bowler, Derby Style Black Hat, Might also be a Bucket Cloche type style.
I think the main fabric used is a nylon netting. 

Hat has tightly placed netting that creates a wavy effects and a unique visual. There is also a rose / flower in the front and the hat is wrapped in a velour trim. There is wire in the brim can be adjusted. 

The style harkens back to the 1920s bowler, derby style, but includes unique fabric choices and that gives a nod to the mod / gogo / retro elements of the 1960s. 

Condition - This item was worn and stored, it is not in perfect shape as wire is not a perfect oval and the rose is a little flattened. You can see it is a little off on the right side of the 1st photo. Also last photo you can see the wire. However it a very unique Clover Lane hat and elements can be worked with, removed or added in case a designer wants to upcycle this item. 

Size - There is no label, see measurements below
Resting the hat is right around 9 inches front to back.
Inside 7.5-8 inches across - There is some give but not a lot. 

A unique hat to add to a collection, wear to a themed 20s or 60s party or Halloween. I could see twiggy wearing this in a photo shoot. 

This comes from a smoke free home and was a relatives.