Constant Power Technology™ - maintains constant speed under load for unmatched cutting performance. Patented Gear Protecting Clutch - extends gear and motor life by absorbing high impact forces caused by sudden blade lock-ups. Patented Counter Balanced Mechanism - smoothest running, lowest vibrating reciprocating saw in the industry. Quik-Lok™ Blade Clamp System - provides fast and easy blade changes. Also has orbital action.