Specialist ID's Clear Horizontal Permanent Locking Plastic Card Holder. End Piece Snaps Permanently Into End Of Card Holder To Lock Cards Inside. Must Break The Holder In Order To Remove The Cards. End Piece Included And Comes W/ Slot & Chain Holes. Holds Two 30 Mil Cards Or One Proximity/ Prox Card Insert Size 3 3/8" X 2 1/8" (86 X 54 Mm). Great for your work ID badge or key card that renews annually or doesn't need to be removed from the holder to have card reader access- Great for office workers, maintenance techs, production operators/laborers.