Sector F Lambda Complex is one of the seven main sectors of the Black Mesa Research Facility. It is connected to the Yellow Line of the Black Mesa Transit System. There can be found the heavily fortified Lambda Reactor Complex, site of Black Mesa's top secret teleportation labs, mostly made of a huge reactor consisting of the Lambda Reactor Coolant System, and the cylindrical Lambda Reactor Core. The core of the reactor facility consist of four levels (A, B, C, and D) that fuel an extremely powerful interdimensional Portal located on Level A, where Survey Teams are equipped, and sent over to Xen.