Hot tuna purge dive mask the hot tuna purge dive mask features a one piece curve lens with a wide view heavy duty frame for ultra clear and full vision complete with double purge valve for easy water clearance dive mask one piece curve lens for clear vision double purge valve wide view heavy duty frame high strength tempered glass hyper dry mask design for leak free precision fit fully adjustable head strap conforms to bs en 16805 2015 safety standard not for pe