Transport case for Spark Plugs. It keeps the Spark Plug clean and dry and protects the electrodes from damage. Even strong vibrations while driving won't harm the Spark Plug inside the case.
The “shelf” beneath the Spark Plug with the core holes is designed to hold a few carburetor jets as needed. Since there are many different jet sizes, you’ll need to drill the required hole diameters yourself.
When arranged in a loop, a few spare cables also fit nicely around the outside of the box—for example, for the Clutch, gearshift, or throttle.