A little update about my knobs. There done!! The only thing that I need to do is take beautiful pictures and place them in my shops. This will happen very soon.
The prices are also fixed: the 4 cm knob will cost €9,95, 5 cm €11,95, 7 cm €14,95 and 10 cm €27,50.
At first I also had a bigger one, 13 cm, but it got to expensive and heavy, that I replaced it by the 5 cm one. This way for the eye they increase beautifully in size.