The Powerslide TRINITY Stride Control contains small little plastic wedges which can be placed under the heel and ball of your skates. The smaller wedges will be used under the front mounting blocks whilst the bigger ones are used on the rear mounting blocks of your skates. The wedges can compensate for physical deformation like pronation or supination, which can cause discomfort and pressure points in your skates. The wedges correct your position on your skates and improve the comfort for better performance and more fun on skates.