Designed to screw onto smaller mason jars (~12-16 oz.) with a 70mm diameter opening. While mouth cutaways were included to minimize contact with the plastic while drinking out of the jar, it is still recommended to print with some type of food-safe material. The blue handle pictured was made with Taulman T-glase for example, which is FDA approved for direct food contact.Position so that the handle is sticking straight up and it is upside-down, as shown in the picture with the handles in different colors. You will need supports for the overhangs for the mouth cutaways and thumb groove on the handle. Mine turned out fine at 35%-40% infill with 3 perimeters, but you can play around to see just how much structure you really need for your jar and whatever you're drinking. I've tried ABS, PLA, and T-glase and they all seem to work well. Cheers!