From Ocean Rodeo:
Introduced in 2003 on all of our kites the Shock Strip (SxS) is a strip of Dacron that runs the width of the kite from wing tip to wing tip. This strip runs exactly over the apex of the kite’s curve and is designed to bear the load of a hard nose down crash. When a kite is crashed hard nose down onto the water a violent shock erupts from the leading edge down the center strut. In many other brand’s kites this will lead to a catastrophic tear along the center strut. With SxS Technology on our kites this Dacron Shock Strip spreads the load of this force out to the wing tips and often saves the kite from damage. If the shock is too severe and a tear does form it is often contained between the Shock Strip and the Leading Edge. This will allow you to safely fly into shore and inexpensively have the small tear repaired.