The low energy limit of M- theory compactification on Calabi -Yau threefolds gives rise to 5 dimensional N = 2 supergravity. By using the attractor mechanism we can obtain BPS as well as non-BPS attractor solutions. For two parameter models we found that non-BPS black holes are unstable i.e. they decay to its BPS and anti BPS constituents which confirms the Weak Gravity Conjecture (WGC) . We also found that several non BPS strings are stable i.e. they don't decay into its constituents. This means that volume of the representative class corresponding to the black string is less than the volume of the minimal piecewise - holomorphic representative. We also discovered that there exist multiple non BPS black string attractors for these strings, which indicates the existence of volume minimising representatives in the same homology class having different values of their local minimal volume as predicted by WGC.