I think it was Quaker State FS 4x4 oil in the clear 1 quart bottles.
I still have a bottle of QS in a clear bottle. I loved those bottles! If they sold it that way today, I'd probably buy it and run it.
One neat thing...It is a bottle of 10w30 and it sat undisturbed for a number of years. There was no settling or separating of any components. It looked the same when I picked it up, looked at it, and topped off a lawnmower as when it was new.