Using Lehigh's Maximum Expansion bullet technology, Underwood is proud to offer a self defense load that is capable of creating the largest wound channels of any ammunition you can buy. Designed to expand upon contact with a fluid-based medium, these cavernous hollow points expand through hydraulic energy meaning they will not expand on hard, dry surfaces. By combining this with flash suppressed powder and nickel plated casings, Underwood Maximum Expansion ammunition is ideal for personal or home defense.