his alloy is a free-machining brass with a 3% lead content - the addition of lead is finely dispersed throughout the microstructure of the material which acts as both a lubricant and chip breaker; this results in giving the alloy its free machining characteristics. With a machinability rating of 100%, CZ121 is the standard by which all other copper-based alloys are rated. The alloy also offers good corrosion resistance and strength.