First off, the child-proof packaging is NO JOKE. I had to wrestle with scissors to free these batteries—kudos to Duracell for making it toddler-proof, but maybe ease up a tad for us adults? Once liberated, they slid right into my car key fob like it was made for them.

The bitter coating is genius. I (accidentally) touched one to my tongue while installing it—yep, instant regret. If a kid somehow gets past Fort Knox packaging, they won’t swallow it. Peace of mind level: 100.

Performance? Flawless. My key fob went from barely working across a parking lot to unlocking my car from what felt like a mile away. These little coins outlasted my old no-name batteries by months. Worth the extra cents for the Duracell stamp.

Pro tip: Buy a multi-pack. You’ll need them eventually, and that 10-year shelf life guarantee means they’ll wait patiently in your junk drawer until the next emergency (glucose monitor midnight crisis, anyone?).