Rick, I have had a British - made Racal positive pressure face shield for a long time (more than 20 years). Polycarbonate face shield (theoretically replaceable when scratched), has a rechargeable battery pack in the headband itself, replaceable filter also in the headband, came with a little air manometer which showed when the filter was losing efficiency, needed changing. I bought it after reading a recommendation by Richard Raffan, the New Zealand turning maestro. I am not sure if the company still exists - the product may have outlasted them.
Works great for turning, but I cannot use over-the-ear noise protectors (3M) with it, and I find the in-ear types do not stay in my ears. As I get older and deafer, I find my self more intolerant of loud noises, especially tools in a confined space. Turning is just bearable, provided there is no chatter on a spindle.