If you are looking for a cylinder, the correct length of the profile cylinder is very important, it depends on the thickness of the door and the matching door hardware. Measuring a cylinder lock is not complicated. To measure the length of a cylinder lock, measure from the centre of the profile cylinder, where the fixing screw that secures the cylinder lock is located.
The standard length of a cylinder lock is 60 mm, which is equal to 30 mm on the left-hand side, or outside dimension A, and 30 mm on the right-hand side, or inside dimension B. The length can be extended on both sides by 5 mm. On thicker doors than 40 mm, the lock is often not in the centre of the door, so the length of the cylinder lock must be adjusted accordingly.
Therefore, for example, if you measure the length 45 mm on the outside dimension A and measure the length 50 mm on the inside dimension B, you will have a cylinder of size 45/50. If, with this same profile cylinder, you want a knob on the inner sides, this becomes a cylinder 45/50 knob or 45/50K for short.
More info on the size of a cylinder can be found on our info page: CYLINDERS