16mm triple square socket with a 1/2″ drive, also often called a 12 point or xzn socket. The service manual refers to it as tool number 2567 and/or 3357. Applications where it is needed: – MKV and MKVI, R32 and Touareg only: – removing the rear calipers when changing brake pads or rotors. – VW, Audi, and Porsche Transmissions that have a tamper proof drain plug, it is needed to remove the drain plug when changing the transmission fluid. _gsrx_vers_436 (GS 6.1.1 (436))