Mostly as very good quality product that fits easily to the windows and generally last; this time I finally bought 6 of my 'missing' velux blinds to complete the upstairs (12 veluxs in total in the house I built 20 years ago) and while these last 6 windows blinds were not essential they look good and will help retain heat and prevent some sunlight damage - the trigger really was the Black Friday sale prices, worth waitng for....