PolyPhoenix - Copper U-Bend with Silicone Tube

A U-Bend is used to prevent vapour flow through the bubbler plate down comer. 
This particular u-bend comes with a small piece of 12.7mm Heavy Duty Silicone.
It is primarily used in conjunction with a PolyPhoenix Bubbler Plate Assembly at the very bottom.

Silicone is a high temperature and chemically resistant material that will not leech anything into your spirit.