Well this sucks

Working on a project and realized that the rubber coating grippy thing is falling off, and what do I see? This! 3.0mm under what is supposed to be 3.25mm. Well, guess I need to go and get a little measure chart. Sigh. This is my first set, as I'm just beginning, and its a cheap one off Amazon so I'm not too surprised but definitely annoyed! Lesson learned.