Meet the Knockout: a bottle top attachment that turns any beer bottle into a beer bong or gravity bong. Just seal it onto any bottle, and you will be able to drink without any spills. If you take the bottom piece off, you will be able to drink faster. The Knockout is made of stainless steel and food-grade silicone. You can break it down for easy transportation and storage.
The Knockout is dishwasher safe and easy to use. It can turn any bottle into a beer shotgun, water pipe, gravity pipe, beer gravity pipe, and more. Sets you back under $40.