Biometal Model FX is the Mega Man transformation for Vent (Mega Man) or Aile (Mega Man Zx) from Mega Man ZX by combining Model F (Mega Man) with Model X (Mega Man). It's design takes inspiration from Fighting Fefnir (Mega Man) from the Mega Man Zero series.
Similar but not the exact same as Atlas' Model F, Model FX can be identified by the arrow design on the helmet present across most biometals combined with Model X.