These are zinc plated or 304 stainless steel double ear clamps that are ideally suited for both maintenance and O.E.M. applications (light duty for air, water, fluids - not for propane or critical applications). They are a quick and easy clamping method also used for rope, tubing, cable, etc. When installing, choose a clamp that just fits over the OD of the hose with a barb installed, then crimp each ear evenly going half way at a time (using proper pincers, not pliers). Choosing the wrong size, using pliers, over pinching the ears, or pinching in a non-even manner can break the clamp. For more aggressive use, we also offer a heavy duty N66H- version in the zinc plated series (sold in full bags of 100pcs only).