Photos of CODE drifters:

The CODE style drifters have drogues right at the sea surface, so they respond much more to the instantaneous wind forcing. The small ball floats help keep the drifter upright and the currents push the "X" shape through the water. The GPS reciever and satellite transmitter antennas are seen sticking up from the top of the drifter.

Photos courtesy of Technocean, Inc.