Built with Teva’s ultra-sticky Spider rubber for traction on wet rocks, and a proprietary fabric coating to keep the synthetic uppers from absorbing water, the Fuse-ion performed as well as any river bootie we tested. The heel folds down so you can slip into them as if they were clogs. The best part: it still looks like a sneaker.
The "ion" in the Teva shoe is an extremely thin (a thousandth of the thickness of a human hair) water-repellent layer called ion mask that coats the entire shoe, including the stitching. K-Swiss, Timberland, and Scott, among others, also use it.