I had some problems with these out of the box, but it could just be me. I don't have a lot of strength in my hands. I'm the one that always has to get someone to open the pickles for me. And the instructions were a little difficult to follow and understand. They come as a steel tube with a small opening on the sides at the top. Attached to the tube is an obvious mouth piece. It looks like the mouth piece should screw off, and it alludes to that in the instructions. I could not get it off. I pulled and twisted to no avail. So, I was not really able to see what was inside the tube, other than looking through the mouthpiece. But, what I could get from the instructions is you remove the mouth piece, put the tube in the freezer. Once frozen, you put the mouthpiece back on, insert the tube into your beer and screw it on. Then you drink through the mouthpiece. This will only work on bottled beer. It can be placed in your canned beer to get it exceptionally cold, but will have to be removed to drink it. Cannot be used as a straw and the tube is not open at both ends. It doesn't seem to have effected the use by leaving the mouth piece on, it was just really cold. I have not tried this on a beer at warm temperature to see how quickly it can chill it, but I will update when I do. What I like about it is, I'm not a chugger, so my beer starts loosing the chill about half way through. This does keep it ice cold to the bottom of the bottle. Updates to come as I use them more, and perhaps get the mouthpiece off.