This is the positive crankcase ventilation (PCV) valve and hose that connects the valley cover to the intake manifold. This part is required for the 2001-2003 LS6 valley cover, GM Part # 12568002. This is a genuine GM part.
GM Part # 12573109 - 2001-2003 LS6 engine valley cover PCV hose
2001-2003 Chevrolet Corvette
Other LS Engines with LS6 Valley Cover GM Part # 12568002