The VMR model is one of those unique mergers of old and new technologies. The current concept was developed by combining our older MI units from the 1950s and 60s, the first generation Vibra-Might design from the 70s and 80s and our design features of the 90s. The VMR unit features a totally enclosed one-piece body design that operates without the dependency of a starter spring and will start in all mounting arrangements. This is coupled with our revolutionary double diameter piston design. The tapped exhaust port comes standard with our own manufactured port protector/muffler and mounting hardware. Customers often ask how our units can be so small in size and weight and quiet but generate more force than comparative models? We could say it is magic, but we know it is 90 years of technology that makes the VMR units perform so well for our valued customers.