Pack of 50. Abrasive refills with a 1 mm polypropylene backing for the d19 pedicure base. Black refills are moisture-resistant, with a 1 mm polypropylene backing and a silicone base. The abrasive is firm and does not shed. Pack of 60 for the d19 pedicure base. Black refills are moisture-resistant, silicone-backed, with a firm, non-shedding abrasive.