What do the security grades of a lock cylinder mean?

They are a way of measuring how secure a cylinder is under the UNE-EN 1303 standard. The manufacturer classifies the cylinder with a code of several digits, and each digit refers to something different.

For security, two matter most:

• Key security, in grades from 1 to 6. The higher it is, the harder it is to open without the key.
• Attack resistance, which shows how well the cylinder holds up against attempts to break or drill it.

There is another digit that also counts on the coast: corrosion resistance.

The code does not always appear clearly on the packaging, so if you are unsure ask us and we will explain it with the cylinder in front of us. More on how to choose in security cylinders.