Hot Racing XMX157RS33 Progressive Spring Set (3 Pairs) TRAHot Racing progressive 33x160mm tuning Springs for the Traxxas X Maxx 6S and 8S. Progressive Springs are soft at the top of the stroke to provide small bump and chatter sensitivity and ramp up in stiffness as the suspension compresses to resist bottoming out over large hits. Features: cold coiled Springs are designed to use with these progressive Rates spring High quality spring steel construction three progressive spring rates provide additional