This is an air filter intake tube meant for swapping a dodge 12 valve Cummins into a 1967-79 Ford with using an industrial style manifold and a low mount turbo with a 4" inlet. 

The industrial manifold and low turbo are about the only option to clear factory HVAC parts. besides clearance, it's really nice to have the hot exhaust parts down low. Plumbing an air filter in is a little difficult with the clearance requirements, and this tube lets you do that. 
 
4" inside diameter on both ends 

Works with Donaldson B085011 air filter, or about any air filter with a 4" inlet 

This is a premium quality and extra thick silicone tube. it will not crumple under the moderate vacuum conditions that intake tubes see