Cruciform key
![](https://upload.wikimedia.org/wikipedia/commons/thumb/d/d9/Kreuzbartschluessel_BKS.jpg/220px-Kreuzbartschluessel_BKS.jpg)
BKS cruciform key (1950s)
A cross-bit key is a 70 to 130 mm long key with a round key shaft , a cruciform key bit and welded key grip (key head). Three or four ribs of the key bit are provided with key incisions (notches), from which the locking of the cross-bit key and the associated cross-bit security result.