Lisle  Spark Indicator

Works well and definitely shows spark. Almost works too well as it will pick up the spark signal in other wires if they are close together so be sure to hold this on a wire where it is farthest from the other wires. On my Ford I found this to be closest to the spark plugs themselves. The light is nice and bright enough to be detectible in daylight. I would recommend handling this product somewhat gently as the join between the clear plastic housing for the light and the aluminum ends looks like it could be fragile. Mine has been fine so far. I'd give this product five stars if there was a heartier join between the clear plastic housing and the ends. I don't know exactly how this tool works but the 'bulb' is non-replaceable which may or may not be an issue over the long term. It is not a standard bulb as there is no filament that I can see. Thanks to Lisle for keeping more manufacturing in the US. This product is Made in USA as of 2013.

Had no trouble seeing it flashing. I really like this tool as it lets you check for spark quickly and easily.

This tool comes at a great price and is so simple to use. It tests the HT leads in a gas engine for spark. It simply takes the energy that escapes from virtually any ignition wire and uses it to illuminate a small (neon???) gas tube. The better the spark, the brighter the light. It might be hard to see in direct sunlight, particularly with a weak spark, but it doesn't need much shade to view the flash in the tube. The handy thing about this tester is that it is shaped like a pen, or laser pointer and will clip into a shirt pocket. This is a handy almost indestructable tool.

Recieved it in a timely manner.. great to be able to go to the store and get on line price and free shipping... THANK YOU...

I like it becuse it easy to see even if your work area is well lite

Not too much to say about this - Lisle makes great products, and this little tool does what it's supposed to do.

It's an inductive spark indicator - just put it on the wire, and if juice is flowing, it lights up to indicate spark.

Works equally well on OEM wires as it does heavier/thicker aftermarket performance wires.

I bought this and was sorely dissappointed. At first I tried this on my car in my driveway around eleven in the morning. I knew all the wires on my car were firing so I was dumbfounded when it didnt work.

I then drove my car into my garage, turned off the lights, closed the garage door(only for a minute or two) and pulled the blinds back. I cranked up the car in a dark garage and using my flashlight put the spark indicator onto the spark plug wires. After I was sure the lisle tester was on the wire I turned off my flashlight and could see a weak glimmer from the lisle tester.

I returned it to sears and tried the same two tests with the replacement. Same results. I returned it.

Wish I had read the review on this product before I bought it. It does work but the light is very weak. Very hard to see in daylight. Do not waste your money.

I would not recommend. the tester does not work very well. hard to see the light and you have to push the tester hard to get a very weak signal.