Murray space saving, plug in circuit breakers are intended for use in Murray load centers and meter combinations that are rated to accept type MH-T breakers. Check wiring diagram to confirm. To ensure the warranty on a Murray panel is not voided, the use of Murray breakers is required. The triplex breakers provide 2 Single Pole and 1 double pole breakers in half the space. These triplex, 1/2 in. frame breakers are ideal when new circuits are required in a panel that has no available spaces.