A small pair of pliers with a pen spring in the model that fits nicely on a keyring. I used a common pen spring cut down a little bit using snips I use to cut my filament (see photos), you could probably use a whole pen spring but I found it unnecessary and harder to insert mid-print. I put in a colour change 3 layers before the bridging layer for the top of the spring slot so that I can put the spring in and it prints over the top of it, as seen in the photos (I included the gcode I used for this on my Prusa Mini+). You could probably insert the spring after the print but I think might be easier.
I recommend printing with 3-4 perimeters and a little extra infill to make it stronger. Optimised for 0.4mm nozzle and 0.2mm layer height but may work on a 0.6mm nozzle and different layer heights.
I printed it in Esun PLA+ black.
The author marked this model as their own original creation.