Air Pillow

Strengths

The air pillow allows you to insert a thinner 20" inner tube which then gets folded in half and stuck in your seat. This gives a huge ammount of padding for your rear end. It also helps protect the inner tube from punctures.

Weaknesses

Once inserted inside the seat cover you'll likely find that the top half moves slightly to one side or the other. This results in an annoying buldge to the side. To prevent this I got a 12" strip of Velcro from a local clothes making shop, cut it in half and stuck one strip to the seat base and the other insdie the fold of the air pillow. With a bit of careful alignment this then stops the the pillow moving around once inserted in to the seat.

Overall

This is a handy (if expensive) addition to an air seat. The extra padding that a 20" inner tube makes is great and doesn't weight much either. So long as you take measures to secure the two halves (see weaknesses) to stop them moving around you're in for a very comfortable ride.