The AIRE Cheetah Chair is just the standard closed-cell foam seat that comes in almost all AIRE and Tributary kayaks. Some folks may want a spare or an extra, particularly if you own a Superlynx or one of our new Trinity II's, which it also fits in. With a rear pouch and cup holder (please don't let river water mix with your beer unless you enjoy severe gastric distress!), and a "flip strap". The flip strap is intended to run all the way around & underneath the kayak, and back up to the other side. The idea for this strap dates back to when a certain Mr. Ramp, now of AIRE, used to do some ill-advised hair runs all by himself back in the early 80's. He felt that since he could only count on himself for rescue, it would be best to have a way to right an overturned kayak full of camp gear with one arm, without letting go of the kayak paddle in his other hand. For that situation it makes perfect sense.
Whether the flip strap is always a great idea depends on how snaggy the rivers are that you run, and how many compatriots you have along to help rescue your soggy self. If you are doing day trips on shallow rivers, this strap running underneath your kayak floor can obviously catch on twigs & pointy rocks. Many feel it is a bad idea, so if it doesn't make sense to you by all means leave it at home. It just clips into the backrest portion of the Cheetah Chair with two fastex buckles.
Also note that you can "beef up" a Cheetah Chair simply by opening the zipper that runs around the buttrest edge, and stuffing in extra closed cell foam. Most big box stores sell very cheap foam sleeping pads that can be cut up for this purpose. Cheetah Chairs run $59.