When padding in wind and current a skeg can be used to improve the tracking of the kayak and adjust the trim to help keep you on course. The depth of the skeg can be fine-tuned using the  slider by the cockpit side. The advantage of a skeg over a rudder is you do not have to continually apply pressure to the the steering system, however it's not as flexible. You can swap your rudder for a skeg at no extra cost. We use stiff stainless steel rope to control our skegs. 

Below: Kajak Sport skeg in fully deployed position

Sea kayak rudder

Below: Kajak Sport skeg in partially deployed position

Skeg

Below: Kajak Sport skeg almost fully retracted

Skeg