I just got one of these. I haven't used it yet.

Innova is the same dial back i have. I found a penske light , but it does not have the inductive pick up clamp, so will have to find my dads old sears and then can compare all 3 light using an external 12v battery.

Found my dads old sears timing light and decided to do a comparison between the D cell, sears, Innova dial back and an inexpensive no name light. All of the 12v lights were connected to an external 12v battery. They all gave the exact same readings at idle and at full total timing. Decided to try the sears connected to the car on board voltage. What i found was that as i increase the RPM timing would retard a total of 5 degrees at 3000-3500rpm. Connected the sears to the external battery and retard with RPM is only 1 degree. Same results with the D cell, 1 degree retard total. I did not check the other 2 lights this way. I would suggest always connecting to an external battery when setting timing or get a D cell light. My connection on the car was the battery side of the start relay and ground. Dont know why this happens, but it does.

I like the simplicity of my D cell light but I wish it was brighter. Don't forget to take the batteries out when you are not using it for a while. Don't want corrosion to kill it. Costs a lot more than a flashlight.

I tested the other 2 timing lights connected to my starter relay just to be sure everything was i thought and sure enough all the 12v lights retard timing connected to car 12v supply. It looks like the more rpm you give it the more it retards. I was seeing 5 and 6* retard. Connected the external battery, 1* retard and same for the D cell light. Was also seeing spark scatter and timing mark disappearing after 3500, but it seemed to be the inductive clamp picking up signal from the other plug wires. All is well and gonna leave it at 33* total form now. Not sure how much i'm giving up at this setting, but will test it next time out.

Just recently (couple of years ago) switched to a Batt operated Timing light for the race trailer. Makes thing much quicker and convent

I think the D cell battery operated light could be any racers best friend. I just wish it had a brighter strobe.

Dave , do you have a crank trigger on your car ? I just tried my Snap On light & it does not retard . Yes I have a crank trigger . Gary

No, i do not and i have a curve in the distributor. I did fix an issue like this on a small block a few years back by adding a crank trigger. It seems my car wiring is doing something odd to the pick up in the distributor. Not everyone has this issue, but i think some do with all the discussions about retarded timing while increase rpm i used to read on this board years back.

It is an inherent thing that electronic ign's do. some types more than others.