A yellow magnetic keycard marked with X8.
The card must not fall into anyone else's hands, as it can be used to access the secret laboratory.
― In-game description
The Yellow X8 keycard is a mission item in S.T.A.L.K.E.R.: Call of Pripyat.
Description[]
This keycard is found inside the Testing Workshop in Zaton towards the end of the mission Unidentified weapon. It is automatically obtained when acquiring the Documents concerning item 62 inside the workshop. The keycard is necessary in order to interact with the card reader inside Lab X-8 and gain access to the laboratory proper.
Unlike other keycards, this one will remain in the player's inventory forever even after being used.