Have you ever tried to disconnect the yellow connector part from a Medela breast pump set when your hands were soapy? I have, and it's not fun. These parts can be a bear to get apart.
I'm surprised that Medela doesn't include a wrench to disassemble these parts. Fortunately, I was able to easily model a wrench and it has been working great for the past month or so. This version is also compatible with the Maymom brand connectors which I purchased on accident.
Anywho, it's an easy print and your thumbs will thank you for it.