Design - Collapsing Waterproof Sleeve

Design a collapsing waterproof sleeve for sequestering liquids. The sleeve needs to be made of waterproof material and should have the ability to collapse. The desired size of the sleeve is medium, which should fit in a bag. 2” interior diameter. patented product replaces toilet flapper. Drain is unable to passively leak as the hole rises above the waterline when not in use. I am looking for a freelancer with experience in product design and manufacturing. The freelancer should have knowledge of waterproof materials and the ability to design a collapsible sleeve. Additionally, the freelancer should be able to provide 3D modeling of the design and provide recommendations for materials and production methods. Ability to take current files and ensure measurements and threads match to parts available in the market. “Sleeve” is the red part in the attached photo.