This is just a simple funnel. There are several already on Thingiverse similar to this one, but the ones I tried weren't durable enough (either too thin, or no fillet in the area where the funnel transitions to vertical). I designed it on SolidWorks (.sldprt file included) and I intended to use it to make it easier to put pre-workout and creatine powder into water bottles. It works pretty well-the only issue is that the layer lines cause a little bit of powder to remain on the surface of the funnel. Not a big deal, but it does lead to a little bit of waste and mess (this could be resolved by sanding or chemically smoothing the inside surface of the funnel).

I calculated the volume of the funnel to be around 5 cubic inches in its default scale. I printed it with a high infill just to make sure it wouldn't get crushed in my gym bag (infill isn't all that important with this print because it is only a few layers thick anyway.