Light duty brass FBL ferrules are used on hose for low pressure air (1/2" size or smaller), water, welding, and various other fluids (non-critical applications). They must be installed using a crimping machine to provide a smooth, uniform grip on the hose barb. They are NOT suitable with 2-Lug Universal couplings, fittings with long barbs, fittings with poor barb serrations, or any heavy duty hoses like yellow compressed air as they are made of soft brass which will tend to bend easily with weight, impact, or abuse.