Stainless steel 1.4305.

Bright.
Indexing pin ground, not hardened.

Cam-action indexing plungers are used when the indexing pin should not project all the time. Turning the handle through 180° retracts the pin.
A notch ensures that the handle remains in this position.
A stop prevents the handle being rotated through more than 180° ensuring that the pin remains retracted.
Selecting which side the stop is on defines the rotation direction of the plunger.

style A: grip uncoated without nut
style B: grip uncoated with nut

1) stop left
2) stop right