Vintage Hal-Hen Battery Tester Keychain - Swiss Made

This vintage Swiss-made battery tester keychain is a compact piece of practical design history, originally used to check button cell and hearing aid batteries. Housed in its original form and sold as-is after decades in a collector's care, it's a charming functional artifact for those who appreciate well-made tools and vintage engineering. The condition and working status are reflected in the detailed photos—examine them closely to see the character this piece has gathered over time.