This is the ISEO Scew-in Cylinder using a 5-pin open profile* to allow keys to be cut easily, but is resistant to manipulation
This cylinder is also EN 1303 tested and FD60 fire rated. Iseo cylinders are high-quality premium cylinders made in Italy.
Their construction makes them perfect for keying alike and master keying where an open profile is required.
*Due to the size of the 25/25 50mm cylinders they are 4-pin and are not compatible with the 5-pin versions. They are, however, still anti-pick.