Galvanized steel enclosure. Single phase, 3-wire, insulated/bondable split neutral, 12 (1 in) spaces, 20 poles, 120/240 V. Main breaker type BR at 10,000 AIR. Tin-plated aluminum bus bar. Twin neutral with non-removable cross bus. When bonded, unused neutral connections may be used for equipment ground protectors in service entrance application. #4 - 1/0 wire range. Electrostatic powder coat, baked urethane painted. Rotate 180 deg for bottom feed; orientation of main breaker handle consistent with NEC 240-81 requirements because it operates horizontally. 14-5/16 in x 18-3/4 in x 3-7/8 in. UL listed file E52977.