It uses a semi-closed cell foam that works by slowly absorbing the air pressure in fully inflated tires. Then, when you puncture, the rapid release of air from your tire causes them to swell up and fill the tire, keeping you riding on air...almost like normal.
The latest set of wheels from Cadex didn't set out chasing a reduction in weight but rather aimed to balance weight, aerodynamics, stiffness, and comfort. Their design includes a depth of 36mm, hookless bead, and carbon fibre spokes, resulting in some of the lightest wheels available.