Lehigh originated Controlled Fracturing Technology.  These bullets are designed to deliver maximum terminal performance. Controlled Fracturing bullets are produced from either solid copper or solid brass and are pre-stressed at specific points so that after a predetermined penetration depth, the razor-edge petals deploy, releasing an energy spike and then separate and radiate outward from the primary path of the bullet.  The bullet shank, now back to bore diameter, continues penetrating straight and deep along the initial impact path.