These spacers fit between the shock absorber top plate and the vehicle body. It has the effect of pushing the wheel further downward, which causes the vehicle to sit higher up, giving increased ground clearance.
The rear spacers are approximately 22mm thick, and the front spacers are dished on the underside to match the shape of the domed strut top plate, with the outer thickness being approximately 20mm. This gives a theoretical lift of 20-25mm, however, some users have reported lifts of up to 40mm. The exact increase will depend on many factors, such as vehicle loading, fuel level, and whether or not any other suspension components are changed whilst fitting the spacers.
The spacers are made from a tough polyurethane which is slightly flexible and has a very high abrasion resistance.
Raising the vehicle is recommended if driving off-road as the plastic fuel tank can easily be damaged.