Looks like a Rubies helmet - I believe there's a "deluxe" vinyl and a cheapo latex version. I dabbled with one of the latex ones some time ago; dunked the lid in hot water, let it soften, and shoved it on a stainless stockpot turned upside down and let the helmet sit on it overnight. The pot was one of those big, pasta kind of pots with an appropriate taper, and I got a nice ESB flare as a result.
The original plan was to fiberglass the inside of the helmet in order for it to keep it's shape. Never completed the project, but I'm positive it would have worked out.