TUSA Sport Adult Black Series Serene Mask, Dry Snorkel, and Fin Travel Set The Serene mask is constructed with crystal silicone and has been crafted for divers who want a wide field of view combined with a low volume design TUSA Hyper dry Elite dry top technology on our USP-250 stops water from entering into the snorkel The UF-21 fins have an advanced multi-flex long blade design with thrust channel technology for superior propulsion