Incredibly adhesion sturdy enough to hold up 20 lbs. Just peel off the back film and stick it on. For the weight more than 20 lbs rod, multiple adhesive bracket hooks can help distribute the weight of the rod.
Antimbee Clear Plastic Curtain Rod Brackets, Wall Mounted, Modern, 20 Pack
Antimbee Clear Plastic Curtain Rod Brackets, Wall Mounted, Modern, 20 Pack