Wingback metal products are built to last, machined from aerospace grade brass and stainless steel. Use this guide to keep them going for the long haul.

The Key Cache is designed to enhance and complement your key carry, while discreetly adding functionality.

It neatly fits onto your keyring and contains a secure compartment to store banknotes and contact details in case your keys go missing. See video instructions on how to fold a note to fit your Cache below.

Since we first launched the Key Cache in early 2019, we've been grateful to hear countless tales from our community about how it saved them from certain calamity.

One customer said it even came to his rescue after he fled his home during an earthquake. The cash stashed in his Cache meant he could buy medical supplies (or possibly a stiff drink to calm his frayed nerves).

Machined from a solid bar of aerospace-grade brass or stainless steel, the Key Cache has been designed to last for decades, not months.

In brass, the Key Cache will patina as surfaces oxidise and interact with the natural oils in your skin. It will develop into a timeless tool, but can be easily polished back to its original shine with some Brasso and a soft cloth.

The stainless steel and Black Steel Key Cache, by contrast, won't require additional care. They will stand up to anything you can throw at them without losing a shade of their original glory.

When screwed up tight, the Key Cache is hermetically sealed to keep its contents dry. Crucial if you have a rolled up $100 bill in there.

We have tested the Key Cache with GBP, EURO, USD and every other note we can find. The maximum size we have tried is 160mm x 82mm.

To fold your banknote of choice to fit your Cache, use these simple steps or follow the video guide below.

1. Fold the note into thirds lengthways.

2. Then fold the note into thirds widthways.

3. Next, roll it up tightly.

4. Insert the rolled up note into the cap first, then screw the Key Cache shut.

5. Clip the Key Cache onto your keys and next time you leave your house without your wallet that cash could just save your bacon.