Comment by ssl-3

External Torx. They're not so unusual. Even General Motors has used those in some places for eons -- I still have the set of them I bought at Autozone to replace the brakes on a Saturn a couple of decades ago.

The real fucker in automotive fasteners is XZN, aka Triple Square. These are all over VW products.

As fasteners go, they're fine. They work well.

The interface has 12 points, and it looks like something from the toolkit like an Allen key or a Torx bit might be the right choice, but it isn't that way at all: The angles are wrong (XZN angles are based on squares, not hexagons).

But that's OK: They make XZN socketry in factories every day that does have the correct angles. They're easy-enough to buy and to use.

The fuckery aspect is a human factor: Because it looks like it "should work" with a Torx driver or an Allen key, people dive in with the wrong tools and fuck it up for the next guy.