The Xtrig Preload Adjuster (spring preload) allows you to easily change the spring preload on the shock absorber by using an 8mm T-wrench. The preload adjuster is installed instead of the standard spring preload rings. It turns in itself and can thus use the entire thread of the strut. No more countering is necessary. 

For some models it is necessary for the assembly to disassemble the shock absorber, because the lower spring plate is so large in diameter that the spring preload rings can not be removed.