This is Jak's last Eco Power that he achieves. It creates a shield of green eco around him and offers protection from enemy attacks for the time it is active. Also, Jak can traverse liquids as if they were solid. Toxic liquids, such as Dark Eco, do not harm him while the Shield is in effect.
It is slightly similar to Light Jak's Shield ability, with some differences being that the Eco Power is more permanent, though still temporary, and allows Jak to cross liquids