The carbide bits are made of carbide metal (which is 20 times stronger than steel). The carbide bits are meant to be long-lasting. They have flute-like cuts on the carbide bit. These cuts enable the carbide bit to shave the enhancement product off and not scratching it like the diamond bits. The grid scale is determent by the flutes on the bit. Dip and large flutes give you coarse grit. Shallower flutes commonly indicate a finer bit. Carbide bits are a great tool for advanced users and are ideal for removing acrylics and builder gels. They are not to be used on the natural nail. The carbide bits should be cleaned and sterilized before being used on your next client.