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Simple to use - just remove rubber boot from spark plug, insert tester & place tester boot on plug. Must-have diagnostic tool for any engine with a spark plug. Turn the engine over - if ignition is being sent to the cylinder, light in tester glows.
When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.