Factory Original Replacement Head: The construction, performance work, manner, etc. of these refill heads are exactly the same as the grinding heads that come with the foot pedicure kit; Perfect for model BK506. | 3 Different Coarse Levels: The extra coarse- for effectively removing even tougher hard cracked skin; The regular coarse- for softening and smoothing regular hard skin; The gentle coarse- for keeping your good daily maintenance and perfect finishing touch. | Easy To Install: Just one step to replace the refill rollers; suitable for soft, hard, dry, and sensitive feet. (Notice: Check the roller head is securely attached to the device before use.) | Safe & Effective: To remove the roughest and toughest calluses and keep your heel smooth and clean; Suitable for both men and women. | 100% Satisfaction: It's perfect for model BK-506, not for V-601 of CIVYPRO. If you have any question with the item, please contact CIVYPRO team and we'll provide you a satisfatory sollusion.