Here is the external part of the cylinder IZIS.
It's a "double action" mechanism.
There is 5 "pumps" (based on Bramah system) : the 5 small holes
and, in addition, 2 very precise pin-tumblers in the lower part of the main hole (tube of key).
The 2 systems must function together to permit the opening of the lock.
The key has a mobile part, is registered, and non duplicable.