a security improved credit , debit , pass , or cash card is a colorless and transparent semirigid plastic card member with non reflective faces , with no permanent imprinting on the card member to visually identify an issuer , an owner or a card number , but with temporary identification that can be removed by the owner of the card and can be visually read only when backed by an opaque sheet . the card has a bending line across a face of the card member that is a slit through the card with a hinge of flexible plastic film attached over the slit . the card has an opening cut through the card member to allow a person &# 39 ; s finger nail to engage the opening to pull the card from a wallet or to attach the card on a shirt button .