This is a 12mm 12 point socket with a 3/8" drive. It is also often called a triple square or xzn socket.
On most MKII, MKIII, and MKIV VWs this socket is needed for:
- removing the head bolts from the head.
On Mk5 and Mk6 VWs this socket is needed for:
- removing the front wheel bearing/hub.
If you have any questions, feel free to ask.
