Summary

If you need to change the battery of your CITIZEN PROMASTER watch yourself, print this two parts in PLA and bond them together after sanding (180) with cyanolit type glue.

If you want a stronger tool that can withstand for long, you can only print the "T" shape part and insert aluminum pin of 2 mm in diameter Inside the five holes.
Take special care to insert pins so that the visible lenght is identical (2mm is a good size)

Prefer aluminium to steel to avoid scratching the bottom of your Watch.

You will save money to change the batteries yourself.