These blocks are made 7075 aircraFT aluminum for Maximum strength. They are a captured hinge pin system which makes changing the toe simple by removing 2 screws on the back and loosing the 2 bottom screws. The use of the tapered ball hinge pin gives the user a very free floating system that will, if a crash is bad enough to bend the hinge pin, continue to operate freely as the ball can still rotate in the bushing or the arm can rotate around the hinge pin. If the pin does get bent it will likely occur at the weakest point on the pin which is at the bottom of the taper. This area is not in the bushing or in the arm, allowing the system to still function. The blocks have (2) additional 3mm mounting holes that bolt through the chassis , taking the pressure off the diff case screws in the event of a crash.. The kit comes with (1) 2.5 mm drill bit (1)3mm drill bit (3) suspension mount blocks (2) hinge pins and all necessary hardware and instructions.