Cardan's magnetic keycard. Was used for access to the item 62 testing workshop.
― In-game description
The Old magnetic keycard is a mission item in S.T.A.L.K.E.R.: Call of Pripyat.
Description[]
This keycard is required in order to gain access to the Testing Workshop in Zaton. Cardan will give it to the player after showing him the Gauss rifle as part of the mission Unidentified weapon. It must be used on a card reader near the entrance door to the workshop to open it.
After the player recovers the Documents concerning item 62, it can be given back to Cardan who will give the player three scientific medkits in return.