Review on INMAKER Collapsible Funnel Set, 2-Pack, Large Silicone Foldable Funnel for Water Bottles and More - Convenient and Space-Saving Solution! by Nicole Cook

I bought these funnels to transfer filtered water from 1 gallon bottles to 1 liter bottles. The problem is that the silicone creates suction so little air gets through, slowing down the movement of the water. You need to raise the funnel to allow the water to flow freely. They also turn over when they are more than half full. If you're using a wide-mouth jar this isn't a problem, but then why would you need such a small, narrow spout for wide-mouth containers? I pour from a bottle with about a 1" neck into a bottle with about a 3/4" opening. I gave them away and bought a more rigid non-separable silicone funnel.