ACUITY 6” to 3.5” Aluminum Velocity Stack6" (152mm) inlet with barb feature to help better secure air filter Reduces to 3. 5" (89mm) outlet 2. 35" (58mm) overall height Parabolic reduction for improved flow 5052 aluminum construction with matte black coating for corrosion resistance Great for adapting a 6" filter to a 3. 5" pipe or for reducing turbo inlet losses Spun from 5052 aluminum to a parabolic profile, this velocity stack is a great way to adapt a filter with 6" (152mm) opening to a