Test the limits of your hot wheels vehicles with the super boosted performance of the track builder system power booster kit add insane speed with power boosters when competing with friendsr build up to 4 different races with this versatile set the stackable boosters are shaped like an arrow and they propel cars for awesome stuntsr the power booster kit includes one hot wheels car 35 pieces including 2 speed loops and 2 boosters so you can boost your crash your loops and head to head race