This is a full set of pistons and comes with the rings and pins.

I will say right off I am not a Fiat parts guy, so any corrections in my information are welcome and appreciated.

The top ring is chrome, I believe.

The piston set is 64.00 mm, which I believe is standard size.

I have seen pictures of other 850 pistons on eBay and they have a flat top.

These pistons have a domed top, which indicates a higher compression ratio.

Inside the skirt of the piston it says "Mondial", "Piston" and "2161 G".

Also on the box it says "66.6210 Std." which is crossed out so I do not believe it is relevant, and could mean this box is not correct for these pistons.

I do not have an OEM Fiat part number, price or availability for these pistons.

This information was passed on to me, and I believe it is accurate:

FYI: I wouldn't consider myself the ultimate 850 expert but I can tell you what I think you have. The box and the parts don't match. Everything on the box would indicate that the pistons are the stock Fiat 850 parts for the early 843cc engine, '66-mid'68 (in the USA). The box info lists stock compression, etc. The pistons, however, are actually the 64mm items used from mid '68-69. The 1mm smaller diameter dropped the displacement down to 817cc. That allowed Fiat to exploit a loophole in the new USA emission laws that exempted motors under 50cid. Starting in 1970, the bore was returned to 65mm and the stroke was increased to make the motor 903cc. Looking at the small dome, I'd guess the pistons to be about 10.0-1, maybe 10.5. Bottom line: probably fit 68-69 817cc coupes, spiders and sedan (68-71) engines.

All applications are accurate to the best of my knowledge, however I advise double checking with your dealer for application to your vehicle, or email me with your VIN # for clarification. I can not be responsible for inaccurate or missing application data, however I will take an item back if the error is mine.