The flexible spring cable on Voile's original Switchback Telemark Binding was pretty revolutionary even though it came with a price, and although the Switchback X2's cable is more durable, it can still break. Voile sells replacement cables in a set of four so you can have spares ready for a while. The Switchback X2 Spring Cartridges are 25% stiffer than the original cables.
Set of four spring cartridges for Voile's Switchback X2 Binding
Cartridges are 25% stiffer than the original Switchback