The X-Vu Mask has small horizontal bumps between the frame and the skirt to prevent this mask from squeezing a diver's face and forehead, especially during long dives. These ribs absorb and redistribute the pressure exerted by the frame onto the skirt, with a resulting increase in comfort. Two-button buckles and an X-shpaed strap allow for easy adjustments to pressure. Weight: 174g.Two year limited warranty