For opening the pinball head on Bally / Williams pinball machines built from 1990 onwards
The head lock is secured with these screws.
Also, many toppers are secured to screws with this wrench size.

The set contains seven common ones
Customs key.
When folded, it is only as big as a pocket knife: 94x25x19mm.
Material: CR-V steel
(Chom-Vanadium = alloyed tempering steel 900-1200 N / mm²)

Allen key set. Inches: 0.05 1/16 5/64 3/32 1/8 5/32 3/16