The Concero is the smallest of the single-window masks, providing a compact fit on the face. With buckles attached to flex tabs on the skirt, it also folds into a compact package for traveling. Of course, being a bit smaller than the other single-window masks, its horizontal field of view is a bit smaller too. However, vertical field of view is on par with larger masks. Squeeze buckles release strap tension with large dual buttons that are easy to adjust on the fly, while the 3-D split strap wraps around your head without bruising it. The round-edge face seal feels soft and kind of sticky — a good thing — for a snug, watertight fit.