I printed using measurements from my original toilet flapper since the standard blue flapper doesn't work.

The parts are glued together and the rubber seal is fitted in between.

The diameter of coverage of the flapper is 70mm.
Distance between the hook holes of the flapper is 29.25mm (blue flappers are 35mm+ so it doesn't fit in my toilet)
Re-use the rubber seal found on the flapper.

Printed on: Ender 3 S1 | PLA+ | 0.2mm | 35% infill | Brim