Rotate Ion Shields

Use this Stratagem when an enemy unit targets
an Imperial Knights Vehicle unit from your army
that has an invulnerable save (this Stratagem
costs 3 CPs if the targeted unit is a Dominus
Class unit, otherwise it costs 1 CP). Until the
end of the phase, the vehicle unit’s invulnerable
save is improved by 1 (to a maximum of 4+)