Nukeproof super light steel springthe nukeproof sls spring has gone through a unique heat treatment process to alter the chemical composition of the metals our unique process changes the siliciumchromiumsteel alloy mix to produce a super hard yet lightweight metal that will withstand the highest demands inflicted through mtb to prevent shock rub the spring is bi convex in shape this will allow the spring to progress freely without any friction when under load up to 40 lighter than a stee