BR style 1 in load center, main circuit breaker, no feed-thru lugs, 100 A, 1 ph, 40-pole, 40 circuits, 20 spaces, 120/240 V, #4-1/0 AWG Cu/Al at 60 or 75 deg C wire, three wire, NEMA 1 enclosure, d1 box size. Interrupt Rating 25 kAIC. Aluminum bus. Combination mounting. 5.19 x 14.31 x 25 in. UL 50, UL 67. Cover included.