The Square D QO 50 Amp 2-Space 4-Circuit Spa Panel Main Lug Load Center with a QO 50 amp 2-pole GFCI breaker installed. It is UL Listed for residential power distribution. This spa panel is built with a shielded, tin-plated, alumininum bus bar that is plated for reliability. QO load centers are tested and are only compatible with Square D QO circuit breakers. QO breaker boxes are the "World's Finest" designed with industry leading features for flexible application.