Place the Spark Plug into tester hole 1 or 2; If you want to compare the new spark plug and old one, place new spark plug into hole 1 and the old on into hole 2. Turn the key switch 4 clockwise to turn on tester, indicator 3 will light up, tester is now working at 1000rpm/min.

Brand: ANCEL
Manufacturer Part Number: 12V Gasoline vehicles car spark plugs
Type: Spark Plug Tester
Vehicle Type: Passenger Vehicle
Volt: 12 Volt
Accessories: Ground Wire
Warranty: 1 Year
Functions: Test spark plug performance and ignition strength
Package includes: 1pc x Spark plug tester;1pc x Power Adapter
Placement on Vehicle: Left
Fitment Type: Direct Replacement
Color: red