The CTA 8mm XZN Socket Wrench with Ball Head, No. 3910, is designed for removing and installing the oil drain plug on 4.2L FSI, 4v V8 engines as well as the removing and installing the intake manifold on 2.0L TDI i4 engines by allowing for removal without the need to remove the fuel rail. The tools overall length is 5.1". It services Audi 4.2L FSI S4, S6, S8, A6, and A8 and VW 2.0L TDI Jetta, Golf, and Beetle.