The Screedemon reduces wet screed hand/arm vibration by 50% to 90%, reducing the risks of white finger, carpel tunnel syndrome, and chronic arthritis. Plus, its rigid back-to-back double triangular design offers uniform vibration along the length of the bar. The link between the wet screed's engine and eccentric is a durable flex coupler that eliminates high-maintenance flex cables or rigid shafting. MBW Inc., 800-678-5237.