There are various types and sizes of Flood research facilities. Many were built on the Halo installations, including the Library structures, the Cold Storage facility below Installation 05's surface, and the Lockout facility, suspended in a mountainside. One facility was built in a Gas Mine in Threshold's atmosphere. Some facilities even have their own Monitors and unique types of Sentinels, such as Line Installation 1-4, a sprawling underground complex on an unnamed Moon. Installation 05's Cold Storage facility also had its own type of monitor, suspended to a ceiling. Installation 00 is known to possess at least one Flood research facility. Containment Protocols were often an integral part of the security in Flood research facilities.