The ATL12D2 also supports a peak handling power of 1200w and nominal handling power of 600w. The ATL12D2, however, utilizes a 1” tall rubber surround for big excursion, versus the B12D2’s Nitrile Butadiene rubber surround. The Atlas ATL12D2 also features a dual 3” voice coil on an aluminum former, a 140 Oz. Magnet, a ported nickel plated back plate, and a single flat Conex Spider with woven tinsel leads.