It never fails. You sit down for a nice, cold beer and for whatever reason, you're forced to put the beer in the fridge while you go run an errand.
These Beer Savers are designed to fix this problem. The caps are made from food-safe silicone, and fit just about any size of beer bottle. (The could be used for soda bottles, too. I guess.)
The caps are dishwasher safe and reusable, and could be useful at the beach or camping as well, to keep beer from spilling or getting lake water into your brew.