Back surprise spring 82mm - 3-Dots provides a mixture of progressive & linear characteristics. The reduced design really helps to attain reduced trip height on high traction songs. The springs are somewhat progressive, but under more compression modification characteristics to be more linear. Thus giving exceptional feeling and feedback in all different track conditions. These XRAY shock springs, like all other XRAY springs, are by hand measured, selected and matched into pairs to guarantee exactly equal length and damping faculties.