The Viper SL is a breathable and lighter version of the Viper. Air mesh upper provides maximum breathability for maximal comfort. Viper SL also comes with a new tounge construction for a comfortable fit and the stability you need on the court. The lower part of the shoe has all the features of the Viper and the construction gives a nice and snug fit and keeps the foot in place properly. It also offers lightweight cushioning and a nice close-to-the-ground feel.