Access code disc
Access code disc is a key found in the level 13th Floor in Tomb Raider Chronicles. It's found after pressing a button, which causes an orange VCI Worker's suit to come out of a locker, dropping the Access Code Disk to the floor.
The Access Code Disk is used on a couple of occasions to open doors.
There are two other similar looking access disks in the VCI Section of Tomb Raider Chronicles: Iris Lab Access and Teleporter disc.