Forged from high quality, chrome vanadium alloy steel . Contains socket sizes that easily remove and install the spark plug sizes common to most vehicles. Packaged in a blow mold case . Fully guaranteed This set is to assist in the easy removal of spark plugs. This set contains socket sizes to fit the spark plugs common to most foreign and domestic vehicles. This set is packaged in a blow mold case and is backed by the Sunex Tools . Forged from chrome vanadium alloy steel and fully polished.