This is 10mm Federal Hydra-Shok 180gr. Hollow Point Ammo. Federal Premium handgun loads are the best around. Hydra-Shok is the choice of law enforcement agencies nationwide, Federal's unique center-post design delivers controlled expansion and the notched jacket provides efficient energy transfer to penetrate barriers while retaining stopping power. The deep penetration of this jacketed bullet satisfies even the FBI's stringent testing requirements. This ammo has proven stopping power. This ammo comes packed in 20rds. per box.