Square D QO 125 Amp 12-Space 12-Circuit Convertible Main Lugs Indoor Load Center. UL listed for residential, commercial and industrial power distribution. This load center is built with a shielded, copper bus bar that is plated for reliability. QO load centers are tested and listed only for QO circuit breakers.Engineered for a quick plug-on neutral breaker connection on every circuit, fewer connections, faster installation and no pigtails frees up gutter space. Includes a combination flush/surface indoor cover, PK12GTA ground bar, and is convertible to a main breaker load center with the installation of QOM1 main breaker (sold separately). Accommodates plug-on secondary surge arrestor (sold separately). Overhead/underground feed simply by rotating the device before installing.