2 WAY SPONGE FILE ARE SPECIALLY DESIGNED FOR PROFESSIONALS OR HOME USE. THE SHAPE OF A CRESCENT ALLOWS YOU TO GET THE HARD TO REACH CORNERS OF YOUR NAILS 220/280 GRIT FOR DELICATE NAILS- WILL NOT TARE OR BREAK NAILS, CAN BE USED FOR PET (220/280).3 WAY BLACK BUFFER PROFESSIONAL & DIY FOR SANDING AND BUFFER, FILE TO SMOOTH NAUTURAL NAILS AND CRYLIC NAILS, GEL NAILS, CAN USE FOR PET, WASHABLE & SANITIZABLE (80/100/100 ).