(EJ Series (5-3/8")) Built for the Subaru WRX... A good aftermarket damper protects your crank. Fluidampr is in a class all by itself, because it is designed to provide maximum control of all engine harmonic vibrations, regardless of the rpm at which they occur and regardless of the crankshaft's natural frequency. This translates to maximum protection of the crank, main bearings, related engine components and more consistent power output. Also, Fluidampr is maintenance and repair free. Fluidampr is effective on both race and street Compatible with:. Other dampers on the market use rubber or elastomer as the insulator for the internal flywheel. Rubber deteriorates and wears down from repeated movements. In laymans terms, the more you work it, the weaker it will get. The inertia ring that balances an elastomeric damper becomes unstable when the o-rings start to wear. Think of it this way, what does a car wheel feel like when it looses one of its balancing weights? How would a fan missing a blade function? A damper with worn o-rings can unbalance a crankshaft and destroy it. The reason car manufactures install elastomer dampers at the factory is not for performance but for cost. The rubber dampers are cheaper and easier to make. Scroll over the picture on the right to see what makes the Fluidampr unique.