Ceramic Fine & Medium 3/32 Barrel Ball(c)
The best feature about ceramic coated bits are they don't heat up in the same manner as other bits. Long lasting, with flute like cuts embedded in the bit for quicker filing. With a universal shank of 3/32", it fits most nail drills/ files and has the ability to be cleaned properly without damage to the bit itself.
You choose your needed grit, fine or medium.