This product has been around for years, but for those who have never used it, it helps prevent metal rotors and hubs from sticking together due to corrosion. If they stick together, cutting through and removing the rotors and hubs can be a real hassle. Put a little CRC on the copper before reinstalling the rotors and next time you need to disassemble the parts it will be easy. The brush attached to the lid is intentionally curved, so don't think it's broken because you'll soon see that it getsβ¦