National Geographic Snorkler "Expedition Series" 100% Silicone , Hypoallergenic mask - Deep Blue * Low Profile Double pane Drop Down CE Tempered lenses. Frame-Lightweight Delrin? and plastic. * Mask Strap-flexible and replaceable with - 3 point hold. Ratchet Quick lock (RQL?)- mask strap adjustment * Mask Skirt-feathered edge seal * Nosepiece-pliable and non-feathered for ease of draining