These are the M8 nuts that are used to Bolt theTurbo to the Manifold, egr pipe to the exhaust manifold and the turbo to the dump pipe.
The studs and Nuts get affected by the amount of heat around the turbo - we recommend replacing them when you have the turbo off or manifold apart - as its a very painful exercise to have the nuts come loose after a short period or have the studs snap as you are tensioning them up.
SOLD INDIVIDUALLY
We also sell the Studs separately or in kit form for different models of vehicle- so search our other listings for these kits