When every NES system was being made in a factory they needed some way to quality control the systems. These carts were used by factory assemblers, and by repair workers. A few of these carts surfaced from old nintendo workers along the years.

This Particular cart is for testing controllers, sound, television colors and object/characters.
Aside from testing each individual component, you can run an auto-test to diagnose any system issues. Label is marked with "reproduction".