Copper-alloy, 2.99 grams, 42.12 mm. Circa 11th century AD. A pin key of Type IV cast in copper-alloy. The bit is a rectangle with toothing on the leading edge; the locating pin is complete. The bow is a lozengiform loop with a circular void. The shoulder is cast as a simple bulb below the bow. Reference: London Museum Medieval Catalogue 1930, reprinted Ipswich, 1993 p.136 and plate xxix (1). Very fine condition, slight axial distortion. Provenance: found Duston, Northamptonshire, England 2008.