The design also incorporates dimples on the entry surface to extend the boundary layer into the mouth. This increases the effective cross sectional area thus enabling higher total mass air flow compared to standard velocity stacks. The Skunk2 Composite Velocity Stack features a 3.5" inch connection to fit various style of intake pipes or tubing. The Skunk2 composite velocity stacks are a great addition for any application looking to maximize air flow. This item is non application specific. Please verify compatibility before purchase. May require some modification for proper installation. Note: If this product is drop shipping from Skunk2 directly, it takes 3 business days to process the order prior to shipping.