E-File bits come in a variety of materials, shapes, sizes, and grits, with different uses and purposes for each kind. Just like your hand nail files, e-file bits have a grit.
While this can differ from brand to brand, e-file bits tend to follow a generic colour coding to decipher the grit of the bit, just like a hand file. As a guide, this tends to follow
If the bit does not have this, you can speak with the manufacturer or you may be able to try and calculate the grit by observing how big the carving is. I always advise against purchasing electric files, or their bits from third party online marketplaces. The electric files themselves have high vibrations, are too lightweight to control and have no manufacturer after sales care. The electric file bits may be of poor quality, have an uneven grit and can cause more work for the tech and often damage the nail when used, especially on the cuticle area. When purchasing from a reputable supplier, you can receive professional advice and education pre and post purchase.
Many times low-quality bits may remove product unevenly and can be difficult to work with.
Yellow = extra fine
Red = fine grit
Blue = medium grit
Green = coarse grit
Dark blue / dark purple / Black = coarsest grit
For carbide bits, the grit scale is determined by the flutes or teeth on the bit, deep and large flutes give you coarse grit, while shallower flutes commonly indicate a finer bit.
Some bits like a 5 in 1 bit will have more than one grit per bit.
For example a fine grit 5 in 1 bit will have XXF, XF, F ranging from top to bottom or vice versa depending on brand.
You can measure the grit of your nail bit by the number of abrasive particles per square inch. The more particles you have, the smaller they are.
In coarse bits, for example, you will see large particles on the bit and the number of grits will be lower.