This MACO RAIL espagnolette upvc window lock mechanism should have MACO printed into the rail/faceplate, visible with the espagnolette window lock mechanism fastened in place.
There are an additional 2 mushroom cams in the centre for the 800, 1000 and 1200mm long Maco Rail locks.
The backset measurement will be printed into the side of the lock, visible once removed from the window.
To ensure that this is the part you require, we advise you to remove the upvc window lock from your window and compare it to the photo provided here.
Please choose the correct Backset [A], Cam Height [B] and Rail Length [C], all explained in the introduction to espagnolette upvc window locks.