Awesomatix PSSX Progressive Spring System set is designed to add 30% progressivity into the originally linear action of SPR01S and SPR01 springs in all A700/A800 cars.
Updated version of the previously known "PSS set". The PSSX set comes with the new ST69X-30 Screw with wider cap that provides 30% progressivity across an increased range of suspension travel and suspension setups.
All previous ST69 screw versions fit as well (not included). 

With the PSSX set the initial action of spring is softer at the beginning of the compression and becomes progressively harder when the suspension get compressed during downtravel of the car. Our tests showed that the car with PSSX set at proper settings becomes more easy to drive and more consistent at low-med traction conditions and especially on outdoor asphalt tracks.

contains:
2pcs AT119X
2pcs ST69X-30