Working tool - Wheel lock spanner, radial slot

This is not only a key for a wheel-lock spanner, but also a combination tool, since the flattened bottom end served as a screwdriver! The ring was intended to attach a lanyard.

Moreover, the round hole was used to measure and identify the calibers of the lead balls used (caliber gauge, German: Kugellehre); the small diameter indicates that this key originally belonged to a pistol or carbine.

Tools of this type can be dated to the period of the Thirty Years' War (1618–1648).