CIB Slide Blocks are made from high density plastic that slides with ease on coping and rails and also has a U-shaped depression to help balance those stalls and grinds. Easy to install without taking off your plates, these slide blocks are adaptable to many of the most popular plates in use today. Each package includes two pairs of adaptor bars, a silver set for 10 plates and a black set for 20 plates, however, these adaptor bars can be bent slightly to accommodatekingpin angles slightly above or below those two standards.