Get some extra turn in your trucks. Using conventional kingpin trucks, if you place the fat part of the wedges towards the centre of the deck, so the front truck is mounted with the thin edge at the front. This will make the front truck turn more. Doing the opposite to the back truck dewedges the truck and makes the truck power and drive from the back, this help pump the truck forward. This set is a basic slalom set up.

The angle of the wedge is 5 degrees. It is on a 0.25 inch riser. They can be stacked. 

Material is hard to medium. It is not hard plastic. So the riser will not deform when bolted down but will absorb shock and vibrations on use.

Has old and new school hole patterns