Use with oil based stain

I have never used it to spray any stain but it says that you can. Your paperwork tells you what setting to use. I do not have the paperwork in front of me but I know that the power setting on top of the sprayer is set kind of low. Somewhere between 1 and 5.

Yes you absolutely can spray oil based stain with the Flexio sprayer. It will come with two spray heads, one for thicker materials such as latex paint, and then another one called the Detail Finish spray head that you would likely use with your oil based stain. There are charts and guides in the manual regarding thinning and settings. In order to use the detail finish head it'll instruct you to measure the thickness of your stain using the provided tool, and thin if necessary depending on the results.