Review on Compact Coffee Dripper for Backpacking, Camping, RV’s, Travel, Home, and Beyond! by Daniel Evans

This is a very useful gadget if you want to travel with a basic cone filter system without taking up as much space. I just used it for an extended camping trip and it worked really well. It's small (a #4 filter will do, but sticks out a lot), but with a little patience you can fill a 20-ounce travel mug. When folded it takes up almost no space - perfect for a suitcase or backpack (a huge space saver over my plastic bags). The only issue is that the silicone base is slippery and depending on the coffee container, if there is water in the filter it can create a seal preventing air from escaping your mug (I've found this to be especially true for travel mugs). This causes instability and severe swaying as the air tries to escape, causing boiling water to splash onto your hands (and keeping the coffee in the cup indefinitely). I drilled two small holes just past the oval lip on the bottom (see photo) to allow air to escape and now the coffee comes down smoothly. You could probably do this with an ice pick, or a nail, etc. as well.