Found this interesting video of a diver testing an experimental full head enclosure all rubber helmet together with a rebreather. You gotta be a true aquatic rubberist to come up with something like this!
The rubber helmet is created by Hydroglove, a company specializing in rubber frogman suits, latex vintage scuba dry suits made for collectors, surfers and vintage divers! All suits is seamlessly molded from 100% natural rubber and is chlorinated for easy access. Price for a suit: $159.00 – $269.00.