Review on ENA Universal In-Line Spark Plug Engine Tester for Automotive, Car, 🔌 Lawn Mower, Truck, Chainsaw, Motorcycle - Compatible with 6-12 Volt Fool-Proof Operation by Jeremy Tyson

Worked as expected with a Briggs and Stratton lawnmower. Would like to use with lower lighting but the spark on tool coils is very visible if the ignition coil is in good condition (like a toaster coil as one review says). You want to use this instead of just seeing if a disconnected spark plug is firing, as it might look fine then, but then you might have problems if it's under compression. I carefully pulled the end of the tool out of the spark plug based on a comment in the review but there was no problem.