We tried SO MANY suction cups before we finally found the right cup for our Epoxy-Filled Sun Catchers.
Note that the cup has an extra ridge in the middle of the cup.
What that extra ridge does is prevent the sun shining in the window from creating a "hot spot in the middle" of the suction cup.
Without the extra ridge, you would see a bright spot of light in the cup when the sun shines through it. That would distract from the beauty of the suncatcher.
