"Want to access NEARLY MOSTLY ALL doors in the facility? Then the Level-4 card is the card that you're looking for, it allows you to access all of the sectors in the facility, but you're still unable to get behind most doors inside just because you need a higher level. Consider purchasing the Omni-Keycard to access ALL areas¨
The Level 4 Keycard is a currently off-sale item that was purchasable for 150 robux.
It currently still works, giving all owners that dont have a L5 or Omni keycard L4 access. It was taken off-sale in The Heist Update due to it becoming useless compared to Omni. CLASS-D CANNOT GAIN CLEARANCE!