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.