These pulley covers are specifically designed so that you may install the 90mm Popoca wheels on your Boosted Board V2, Mini, Mini X and protect your pulleys and belts. Without these pulley covers you would need to remove the stock pulley covers on your board. This is not advisable as rocks and debris will lodge itself between the teeth of the pulleys and belts causing severe damage to your board. Popoca wheels not included in this set.