Hybrid Racing Cold Air Intake (06-11 Civic Si)The first and perhaps most obvious feature of this intake is its full silicone construction. The 1 4" thick fiberglass reinforced silicone tubing is sturdy enough to withstand engine vacuum and insulates your intake charge better than any metal or plastic intake on the market. This leads to very cold intake air temperatures, meaning a denser air charge and more overall power. Another power adding feature is the included velocity stack. This 6"