Review on 🔧 GRAVITRAX Replacement Chromium for Four Brothers by Tim Knoepfle

Although they correspond to the description and function, they are coated with engine oil or similar. This isn't the best idea for an accessory to a child's toy, and OEM balls don't come in this form. Not sure if it's toxic to my 6 year old so they need to be washed it's generally a bad idea to cover them that way. They appear to have been repurposed to fit the description but were not made specifically for Gravitrax.