A perfin (a contraction of 'PERForated INitials'), also called SPIFS (a contraction of 'Stamps Perforated by Initials of Firms and Society's'), is a pattern of tiny holes punched through a postage stamp. Organizations used perforating machines to make perforations forming letters or designs in postage stamps they purchased, often in bulk, with the purpose of discouraging pilferage. The size and number of perfin holes, and sometimes the design permitted, is usually regulated by law or postal regulation in the relevant country.