Dennis writes, " We used to use the Tyvek, but DuPont has patented a new fabric called NexGen they use on their Proshield line of suits."
I have used this fabric and I guess you just have to pay the price for liquid resistance. It may be cool enough when you sit on a tractor but when you're pulling 300 ft of hose on a slope to spray with a handgun it's torture to wear on a hot day in late spring.