Federal Personal Defense 9mm Luger 135gr Hydra-Shok Deep Handgun Ammo - 20 Rounds - Federal Premium Hydra-Shok has proven itself for self-defense since 1989. Hydra-Shok Deep builds off the time-tested platform with design improvements that better meet modern performance measurements. The bullet features a more robust center post and a core design that penetrate to optimal depths through the barriers most commonly encountered in self-defense situations. Hits Optimum Penetration Depths Through Barriers Encountered In Self-Defense Situations Iconic Center Post Design Has Been Improved For Better, More Consistent Expansion Specially Formulated Propellant Extremely Reliable Primer Penetrates 15 -Inches In Bare Ballistics Gel-The Ideal Depth According To Modern FBI Standards