I designed this to facilitate opening the back of a few older watches I had laying around in order to replace their batteries. I pulled the idea of a spanner wrench style case-opener from another design, and added the pyramid-type spanner tabs to allow easier access to the case back with watch straps still installed.

This print worked alright in PLA. Truthfully, even if it broke every use it would still be worth it to me, because I don't generally change out my watch batteries on a frequent interval. 

The trick to this print is to use a height modifier of the # of perimeters for the protruding tabs. At the very first layer of those tabs I used the height modifier function to change to 5 perimeters. This made the difference in order to break the torque of a stubborn watch case. I'm not very well set up to print in PET-G, but if you are adventurous it may work better long-term for a tool such as this. I used .3 layer height with no issues.