I designed a Suction Cup Clip for mounting papers or as a hanging hook on the glass wall, to keep the wall clean without tape or glue. The structure is from the clip I designed before, which could keep biting tightly without metal springs. You can also download the clip for free at: https://www.thingiverse.com/thing:4849576 You can buy the suction cup with M4 thread screw on Amazon, just search "suction cup M4": https://www.amazon.com/s?k=Suction+M4&ref=nb_**_noss Enjoy!