You get 4 of these for $2.00.
Imagine a fireless firecracker! These are completely harmless but make a loud pop. It’s a square mylar bag filled with baking soda. Inside of that is small bag of vinegar. You can feel the little liquid bag of vinegar inside of it. When you squeeze and pop that bag of liquid you’ve typically got 20 seconds to five minutes before the bag expands completely, pops and explodes. There are variants like the weather that determine the chemical reaction. If you want it to go off fast, then shake it after popping the little bag of vinegar inside. You’ll see it swell up. It’s literally a ticking time bomb. If anything gets on you it’s harmless.
I am notorious for putting them in envelopes and activating the Bomb Bag and giving them to folks as gifts. I do this for a few reasons. It hides the word Bomb Bag on the packaging. It’s less obvious that the bag is swelling when in an envelope. Finally, when it does explode, it’s a self-contained little mess and there’s less of a chance to need to wipe up anything. Do not use these in a moving car. In enclosed spaces they can be loud. What’s cool is you can put them in your swimming trunks and activate them under water and let the little bag float to the surface. They are loads of fun. Just be cautious with them.