CTA Tools 3235 Ramp-Type Spark Plug Gapper is engineered to measure clearances of spark plug gap size. It features a range of 0.02 to 0.1-inches (0.50 to 2.5-millimeters). This spark plug gapper is manufactured with rugged, all-steel materials. Heavy-duty construction allows for strength and durability. California Prop 65 - Warning, This product contains chemicals known to the State of California to cause cancer, birth defects or other reproductive harm.