QO Circuit Breaker Load Centers, QOC12UF, from Square D are Underwriters Laboratories (UL) Listed and CSA rated panelboards. They are designed to meet residential, commercial, and industrial requirements to protect electrical systems, equipment, and people. This keylock accessory is a fixed toggle padlocking device and is mounted in front Locking options are lock OFF only without keylocks for PowerPact L-Frame. Circuit breaker internal accessories are available either factory installed or field installable. They can be installed in accessory compartments behind the circuit breaker accessory cover. This accessory Certified to UL, IEC, CSA, CE, CCC, Standards.