Each lock cylinder contains 3 keys. Hence, if you order for example 4 lock cylinders (simultaneous locking) you get 12 keys with no additional costs.
If you want to order separate locking systems for example using 2 separate simultaneous locking systems you have to conclude 2 separate orders. And if you want to order several lock cylinders of the same series make sure to select simultaneous locking at the corresponding length.
Concerning dual-profile cylinders with danger function: You can close the lock even if a key is inserted on the other side.