Promate Scuba Dive Frameless Mask Snorkel Set Promate Raven Frameless Scuba Dive Mask/MK500: Promate Free Diving Snorkel /SK170 NEW product Line for 2012 !!! Flexible tube & excellent shape memory, and special material and design minimizes feeling of discomfort; even after prolonged use. Designed specifically for spearfishing, free diving, and great as a backup gear mask snorkel combo set.