This is a Boost Tap Manifold for VAG 3.0 Supercharged engine as found in 2010 onwards S4 S5 Q5 A6 A7 3.0T. It will allow connection of a boost gauge to these engines with the minimum of effort.
Audi:
A6 > 3.0T
A7 > 3.0T
Q5 > 3.0T
S4 > B8/8.5 3.0T
S5 > B8/8.5 3.0T
SQ5 > 2012 On