Pair of 3KG helper springs with 55mm ID aluminum separators and 12 stainless steel slip rings. 63mm stacked length uncompressed and 25mm length compressed. ~ Allows you to sag the main spring without it coming loose when the suspension is drooped. ~Allows static ride height to be towards mid travel for a more equal compression and rebound stroke. Very important when using high spring rates so you are not topping out the shock. ~ On drift cars in the front, helpers can give some down travel for drifting a bank with more downhill tire contact if a softer sway bar setting allows. ~ On very low cars, Added down travel assists traversing driveways without getting stuck or teetering on 3 wheels ~ On cars lowered by drooping the main spring, these fix problems with the main spring coming unseated.