Standard files are manufactured using top quality "standard" grade sandpaper.
Premium files are manufactured using the finest "premium" grade abrasive paper sourced from around the world to produce the highest quality and longest lasting nailfile.
Both "standard" and "premium" Black nail files are water resistant (up to 10 minutes of immersion) and will not swell, shred, or peel.
Zebra "standard" files are non-washable and non-immersable! Zebra "premium" files are washable and immersable up to 10 minutes.