This blind does not need screws but of course you can use them. Beige colour (no marks) but blacks out light very effectively. Working order. The up/down mechanism is on the left. I have had shutters put in so no longer required.
The photo of the blind at window is my bathroom one. The longer one is exactly the same.
Self adhesive Black out blind (Newlyn TR18)
This offer has been gifted to someone and is no longer available.