HD SDS 2.0 - 4 spring system. The kit includes a new spring holder for 4 wires + matching receiver + 4 wires in thickness 0.85. Due to the 4-spring-system, there are no more spring breaks and the standing up of the bike in curves is - if desired - eliminated. Overall, the bike with 4 spring wires drives even easier and more precise. The set can be used on any bike that has already been converted to the SDS 2.0 with 2 wires.