This is a self-timer holder for Instax Wide 100, it is based on automatic shutter relese that I bought online. I printed it with PETG, diffrent material should also be good. To assemble it you will need a three M2x5,5 screws, and one M3x26 (it should be hex socket cap), you will also need a M3 nut and, part of a spring from a pen. You also gonna need around 52cm of elastic rubber cord with diameter of 4,5mm and a latch with plastic switch for elastic rubber cord. For a tight fit a used a felt pads that are usually used for chair legs. I advise printing with support, printed with 0,6mm nozzle and brim.
If someone would like to modify the file i uploded STEP file.

No

Yes

0.3 or 0.2

20-30%