Impact Reducer Dual Foam insoles are made up of two essential materials for running: one absorbs shocks and the other is more dynamic, giving you the energy you need from your foot movements. Merrymesh topcover: comfort. Rearfoot section (viscolatex): absorbs shocks. Forefoot section (rubber foam): boosts propulsion. High power sole for impact dissipation and foot propulsion. Bi-material construction allows ideal cushioning at the heel and better propulsion at the forefoot. Very thin (3mm), it can be used under an existing sole or directly under the foot. Prevents joint pain. These soles are very thin and can be used under existing insoles or directly under the feet.