They seem to work OK.

Quickly installed and adjusted. The plane runs like a top ! Will buy again.

Arrived quickly and well packaged . Works well.

Working fine so far. Apparently a good product from Kelly Aerospace.

Installed both mags This mag after installing at annual experienced a miss from this right mag. Thought it may be a spark plug changed suspected plug. Second engine run up this time when testing left mag engine died this time. Brought back in hanger removed mag and the A&P I.A. had to disassemble mag to find that the condenser wire from the points was not plug on to condenser. It was just laying against it and there was visible burn makes on the spade connector. reassembled installed mag and ran engine again now things are fine. I feel quality control should be better than this.

One of the two mags was bad! Will have to send back. At least Kimberly got it corrected in good order

Your on-line catalogue did not give the information I needed (at least not where I could find it) so I called ACS and talked to a woman who was to help me find the Slick magneto models that I needed for my Lycoming O360 A4M engine. I gave her my information and that I needed one with a impulse coupling. She told me that I needed a 4370 and a 4347. Turns out that neither magneto is impulse coupled. So, I went to another source for my necessary information and found that I need a 4371 impulse coupled magneto. So I ordered the proper magneto. Now, I have to return the one magneto to ACS. Another delay for me because the person at ACS gave me the wrong information. Your on-line catalogue needs some work to make it more user friendly!

Had a miserable experience with the 4371 impulse coupled mag. Right after installation, the plane experienced hard starting...both cold and hot starts. Subsequent check of the timing showed they were installed perfectly. After becoming stranded at a distant airport, the mechanic there determined it was a weak magneto. Kelly didnt offer to ship another one, and neither did Spruce, unless one was purchased to replace it. Terrible product, support, and customer service from everyone involved. Two months after purchase, Spruce still has the wrong information about the magneto, saying that the coil and condenser is replaced, which is not true. All around horrible and expensive experience.