Siemens Q23030CT2 Two 30-Amp Double Pole Circuit Breaker
SIEMENS space saving, plug in circuit breakers are intended for use in SIEMENS EQ, SIEMENS Ultimate, ITE, and Gould load centers and meter combinations that are rated to accept type QT breakers.  Check wiring diagram to confirm.  To ensure the warranty on a SIEMENS panel is not voided, the use of SIEMENS breakers is required.   The quadplex breakers provide two double pole breakers in half the space of standard sized breakers.  These triplex, 1/2-Inch frame breakers are ideal when new circuits are required in a panel that has no available spaces.