Our air-intake ducts are precision vacuum-thermo-formed to exacting specifications of race-rested designs to yield the lowest drag and the highest air flow velocity, unlike most other commercially avaialble ducts. These ducts are formed from high-impact 1/8" ABS or Lexan sheets and have extra-wide flanges to accomodate a wide variety of mounting needs. Our ducts have special hose-retention ribs to ensure air hose retention in high-vibration stress areas. Specially designed hose adapter adapts any duct from 3" to 2 1/2" or 2" hose and it just snaps into place. All ducts come in black ABS except AD-D104 which is a clear lexan NACA duct, and AD-D102 which comes in black ABS or Clear Lexan.