Mounts to the carb heat shield.  Excellent hand machined and finished part.  Exact copy of OEM in Stainless Steel.
 
Expensive US sourced stainless.
 
Email about a  combo deal with a new 1600 heatshield for 200.00!    
 
This tube is less expensive than the earlier 65-67 tube and can be used to replace that too.  (all you have to do is add a short section of 1/2" heater hose)