I have one and it has come in mighty handy when we were moving calves in the spring rains.
My horse would be soaked, my saddle would be soaked my duster and hat would be "wet"..
but I was snug and dry on the inside of it.
Also, something else that you need to remember about dusters..
If they get muddy or you get any "cow poo" on them, hang them up outside, and take a hose to them, and wash them off,
let them air dry and they will be good as ever.
You can get them in short, long, lined with warm fur stuff , or unlined.