*Can be used on natural & artificial nails *Filing surface is permanently etched into the glass--will NEVER wear out! *Can be 100% sanitized *The ultra smooth result is the reason chipping, peeling, and splitting is reduced *Safe for babies *Tempered & hardened & is 100% stronger than normal glass *Small is 3.5" long - great for handbag *Medium is 5.5" long - perfect for nightstand *Large is 7.5" long - great for heels & calluses |