This is the traditional crosscut style of spinnaker.  This cut is not as favored as the full radial (linked below) for sailing deep downwind and thus for racing but continues to be a popular sail among daysailors or racers who prefer the more forgiving nylon fabric over the AirX.

The sail includes the number (please indicate your choice of red, blue, black, or green) and the price includes the Flying Scot Sailing Association royalty.