Square D® QO Load Centers, PKSB1HA, service entrance barriers for QO / Homeline®1Ø 150–225 A QOM2 convertible main load centers. This product has been verified to adhere to the specifications listed on the datasheet by the Underwriter Laboratories(UL). QO load centers enable the use of a full complement of accessories. Systems can be single or three phase and have indoor and outdoor versions. This product has been verified to adhere to the specifications listed on the datasheet by the Underwriter Laboratories(UL).