[H]ammering does not simply have knowledge about the hammer’s character as equipment, but it has appropriated this equipment in a way that could not possibly be more suitable [...] [T]he less we just stare at the hammer-Thing, and the more we seize hold of it and use it, the more primordial does our relationship to it become, and the more unveiledly is it encountered as that which it is – as equipment. The hammering itself uncovers the specific ‘manipulability’ of the hammer. The kind of Being which equipment possesses– in which it manifests itself in its own right – we call readiness-to-hand.

(Heidegger, 1927, 15:98)