? Specifications Power Adapter: Input 100-240V AC / Output 12V 1A DC Simulated Engine Speed Range Control: 500-6000rpm Spark Plug Inner Hole Diameter: 12mm Product Size: 145 x 110 x 85mm (5.7 * 4.3 * 3.3 inch) Product Weight: 350 g (0.8 lbs) ? Package List 1 x Spark Plug Tester 1 x Power Adapter 1 x User Manual (Spark Plug Not Included) ? Note Please power off the tester before placing the spark plugs. The tester is a high-voltage detector, so DO NOT touch spark plug with hand at work to avoid danger.