Know by the drop-like shape, the Euro cylinder is very common to European contries. It's operated with a thumbturn or a key on the inside.
To mount the Danalock V3 on a door with an Euro Profile cylinder you will have to replace the cylinder with one that is Danalock V3 compatible.
How to measure without removing the cylinder from the door
You don't have to remove the cylinder from your door to measure the length of the outer part of the cylinder needed. To make sure you choose a cylinder with the right length, measure the distance from the center of the screw hole to the cylinder part facing toward the outside.
The Euro lock door as seen in profile.
The cylinder is either operated with a thumbturn or a key on the inside.
Close-up showing how to measure
Measure the distance between the screw and the cylinder on the outside of the door.
How to measure the length by removing the cylinder
If you are unsure of how to measure the length of your Euro Profile cylinder whilst mounted in the door, you can remove the cylinder.
Remove the cylinder screw, pull out the cylinder, and measure it from the center of the screw hole to the end of the cylinder - remember it has to be the part of the cylinder facing toward the outside.