Duro Dyne - The RAPIT is an inexpensive, rattle-free regulator for quick installation on balance or splitter dampers. It is formed from rust-resistant, heavy gauge, galvanized steel and installs in seconds. The Rapit will penetrate and secure to round or rectangular damper blades up to 24 gauge steel. It has a fully retractable bearing of zinc alloy, threaded to accept a 5/16-18 wing nut and a handle that indicates the damper position. It?s as easy to use as 1-2-3. 1. Slip the bearing over the edge of the damper at the bearing line.2. Lay the assembly on any firm surface and rap the prong with a hammer. One blow drives the prong through the damper blade, holding it securely to the damper.3. When hit with a hammer, the prong will automatically form up tight by the anvil, which is built into the bottom of the ?Rapit? Bearing.