Velux Skylight are very popular in Europe and around where I live found in pretty much every second Home.
Although their build quality is amazing I was getting increasingly annoyed that they only lock in the closed or a barley open State. To change that i threw together a simple part that allows the window to lock in the stock, barley open position, as well as three increasingly further opened positions.
Tested on 1999-2013 models of manually opening Velux Skylights but should work on all model years. Might require some Sanding for the right fit.
The author marked this model as their own original creation.