If you can’t find a commercial one, the next time you’re at a restaurant that has sliced eggs in one of their dishes, offer the waitress or another low paid employee cash to buy one. I know when I worked food service, I would’ve happily swiped one from the kitchen for you for $20. We had a few, so one missing wouldn’t have been immediately noticed.

Also, only use it for eggs. There are other gadgets meant for slicing veggies, and an egg slicer isn’t one of them.