CE12808SD-B1 is CE12808S DC Bundle1 (DC Assembly Chassis, 2*MPUA-S, 4*SFUB-S, 4*PDC-2200WA). Quick Specs Figure 1 shows the appearance of CE12808SD-B1.
CE12808SD-B2 is CE12808S DC Bundle2 (DC Assembly Chassis, 2*MPUA-S, 3*SFUC-S, 4*PDC-2200WA). Quick Specs Figure 1 shows the appearance of CE12808SD-B2.