I really wanted the clean, smooth surface finish of a PLA CF, but didn't want it to scratch the AirPods Pro case when I slid it in and out, so I created a multi-material print that would allow you to set the interior as TPU. This creates a much more snug, reassuring fit (the AirPods will NOT fall out anymore). In order to ensure a user could take their AirPods out when they wanted to without scratching up the bottom of their AirPods while pushing it out, I also created an ejection tool.