On my Saab 93 the socket is an E16 torx head bolt as mentioned in the Head Bolt size FAQ. I have a 2002 Saab 93 2.0T in Canada and it calls for a T40 socket. When I went to buy one, the salesman was confused when I said socket. I then learned that the sockets have an “E” designation, as I later saw in the Head Bolt size FAQ! I hope that’s clearer for future users.