Nail Tools

Kupa Inc. makes electric nail files which are very powerful. The speed can be adjusted by a dial from slow to super fast and the direction switched from forward to backward.
They are best used by trained manicure professionals and only on acrylic or gel nails beyond the nail bed. Otherwise cuticles can be nicked or too much filing on the nail bed can damage it. (It's not easy to see how thin a nail is especially when there's acrylic dust flying around.)
Some salons won't even let their technicians use electric files because of the risks. Very good pros don't need to use them because appropriate application of gels, etc., greatly reduces the need for filing. Use of a regular nail file with optimal grit can save a lot of time and produce a perfect finish.