Spark Plug Tester Dual Hole Spark Tester 0~6000rpm Adjustable Frequency Car Spark Plug Tester Adjustable Dual Hole Ignition Diagnostic Detector Spark Plug Tester Dual Hole Diagnostic Tool Gasoline 12V Car Ignition Spark Plug Tester Dual Hole Diagnostic Tool Gasoline Car Ignition Amazon: Spark Plug Tester Double Holes, Spark Plugs Automotive Engine. FEATURESDUAL HOLE SIMULTANEOUS TESTING: Allows simultaneous testing of two spark plugs, enabling quick comparison and diagnosis of ignition issues in multiple cylinders.ADJUSTABLE WORKING FREQUENCY: The adjustable frequency range (up to 6000 RPM) accommodates different engine types and conditions, ensuring accurate testing across various vehicles.PROTECTIVE COVER DESIGN: Features a robust protective cover that shields users from potential sparks and debris during testing, enhancing safety and reliability.DURABLE CONSTRUCTION: Constructed from high quality plastic and metal components, ensuring durability and longevity even under rigorous use in professional automotive environments.OPERATION STEPSPRODUCT DETAILSSPECIFICATIONPower Supply: 100 240VWeight: 354gAnalog Speed: 0 6000rpmSize: As shown belowPackage Includes: 1 * Spark plug tester, 1 * Instruction manual, 1 * ChargerNOTESAlways ensure the engine is turned off before using the spark plug tester.Follow the manufacturer's safety instructions and guidelines for proper usage.Use caution to avoid injury from electrical sparks or mishandling. Keep the tester clean and dry when not in use to maintain its performance.