Instruct: Classify the given Amazon review into its appropriate rating category
Query: It works very well until it doesn't...

As others have mentioned, this cable sometimes doesn't work properly. I don't know if it's from dirt or debris of some kind, but I have 2 tips (bought one as a spare), and they don't seem dirty, but it does fail to work sometimes, and simply charges slowly sometimes too. It does also get hot at times near the tip. When it DOES work, it works well. I love the idea behind the product. But when I start waking up late and seeing my phone is dead (my phone is also my alarm), that's a serious problem for me. I don't wanna oversleep and be late for work or something because my phone didn't charge. I'm afraid I'm going to have to look for a different cable soon.