 
Motion Control Core (MC2). This advanced core design features “Vertical Dual Density” Technology, a weight block in which the vertical differential of specific gravity is .40 creating built in core mass bias.
The MB/Intermediate differential of 0.01 listed is just an estimate. I wasn't able to find the actual value anywhere.
Core Type
              Asymmetric
          16 pounds
15 pounds
RG
              2.490
          Diff
              0.055
          MB Diff
              0.010