Asics Lethal Charge Rugby Boots Full grain leather upper - Providing fantastic support and shape retention. Rear foot SoLyte In the midsole to give you the best comfort and cushioning for your feet. Solyte is a proprietary cushioning material that provides an exceptionally lightweight midsole with excellent bounce-back and durability. HG 10mm gradient If the heel shifts your body mass forwards reducing strain on your lower limbs.