Copper-alloy, 2.71 grams, 42.20 mm. Circa 12th-14th century AD. A pin key of Type IV cast in copper-alloy. The bit is a rectangle with shallow toothing fore and aft. The bow is circular and the shaft has a bulb and collar at the upper end. Reference: London Museum Medieval Catalogue 1930, reprinted Ipswich, 1993 p.136 and plate xxix (1). Good very fine condition. Provenance: found Essex, England 2005.