This tool is something I made for myself, but maybe it's useful to others too.

I sell a product that comes with multiple m3 screws&nuts. I like to assemble them together as pairs before shipping to rule out any bad nuts/screws, and make sure I don't send a mismatched number out.

This tool helps to align 20 m3 nuts in place so 20 screws can be inserted, then the pairs can easily be retrieved from the flexible TPU.