This one is about 10 3/4 inches long. Not aluminum but not iron either. The nut and moveable blade at the end are magnetic though. You can see a tiny pin on the end of the knurled knob that looks like it would be easily broken or worn off, but it is not replaceable. There are no markings of any kind on it. Thanks
Bruce

piston ring groove cleaner?

I have heard something similar before, but how does it work?

I second the motion. Piston ring groove cleaner.

EvilDr235

You place the arms around the piston. Turn the head to the bit that fits the ring groove. Then rotate the tool around the piston while holding pressure against the 2 arms. The bit cleans the carbon buildup out of the piston ring grooves.

I had a ring groove cleaner, Blue Point I think, but more often used an old piston ring of the same size with good results.

Does anyone still re-use pistons any more ?