When purchasing a foil kite you’ll have two options: Open Cell & Closed Cell.
Open Cell: Open cell foil kites have a double layer of fabric that fills with air to inflate when riding. The cells then deflate as the kite depowers.
Closed Cell: Closed cell foil kites have a one way valve that allows air to flow into the kite, but not out. These kites are unique in that they are foil kites that can actually be relaunched out of the water and are a bit more stable in the wind than its open celled counterpart.
N/A: LEI kites, by design, do not have open or closed cells on them. The Leading edge provides the shape that the cell’s would otherwise create.