This specification covers the Automatic Bus Transfer Switch (ABT) (see 6.4.1) and the Manual Bus Transfer Switch (MBT) (see 6.4.13), herein referred to as ABT, MBT, or switch(es), for use on surface and submarine Naval vessels. Unless otherwise specified herein, this specification applies to both ABTs and MBTs. Requirements for Static or Solid State ABTs (SABTs) are not defined in this specification. MIL-PRF-32150 specifies requirements for SABTs.