this was made to work with  https://www.printables.com/model/1056695-laser-visualizer-of-sound-waves/files. it allows me to use my redmi note 12 phone speaker as source of sound waves. my phone thickness is 7.8-8.2 mm and this works well with balloon membrane as sealing /gasket. it should work with phones of similar thickness.without it the speaker wasnt powerful enough to make the visualizer work