The 10mm socket has a reputation for disappearing exactly when you need it most. So we packed a spare.

The Ko-ken “Break Glass in Case of Emergency” Box is a fun piece of shop merch featuring a genuine Ko-ken 10mm socket displayed inside a custom 3D-printed insert. Inspired by an emergency break-glass box, it gives one of the most commonly used—and notoriously misplaced—socket sizes its own designated backup spot.

The front reads “BREAK GLASS IN CASE OF EMERGENCY” along with “Some heroes wear capes. This one holds sockets.” Flip it around and you’ll find one final reminder:

“Don’t worry. We packed a spare.”

Keep it on your workbench, toolbox, desk, or wherever you think your next 10mm emergency is most likely to happen.

A little Ko-ken merch. A real 10mm socket. And potentially the backup you’ll be very happy you have.