Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:5266253.
WalMart Super Tech Quart Oil Coupler by RebelTaz
We go through a lot of oit in my shop. You would be surprised how much oil gets thrown away in "empty" bottles. We let every bottle drain into a common bottle overnight and over the course of a couple of weeks, we get a "free" quart that would have otherwise been thrown out! Waste not want not, I was always taught. Anyway, I had originally designed this to fit standard quart bottles - https://www.thingiverse.com/thing:3907661 - but I have recently been buying WalMart's SuperTech oil. Their bottles are - just to be contrary - wide mouth and as such, aren't compatible with the standard coupler.
I have verified that this is also compatible with Polaris ATV oil containers, as well...
I took this opportunity to improve on my original design. In this iteration, the lip extends into the catch bottle and the donor side is beveled to act as a funnel. With this design, there is less chance of mess. Plus, it fits wide mouth containers.
I recommend printing with 1.6mm walls, 20% infill and no supports.