Copper-alloy annular brooch

Bronze annular brooch, diam. 3.8cm. Ring oval section, width 4mm, but thickened by 4 flattish knobs regularly spaced. Each flanked by pairs of engraved lines. Between two of them, ring narrowed to waist for back of pin, iron stains here, and wear as from tip of pin opposite.Originally listed as six rings/brooches, but one is associated with the site of Ozengell and the remaining five are unprovenanced – D.H.