Paua abalone (New Zealand Paua abalone) rings size 6.35mm (1/4") outside diameter 4.05mm (0.159") center hole x 1.5mm (0.06") thickness. Some uses include fretboard markers, musical instrument inlay, furniture inlay, marquetry, pool cue inlay and other general decorative inlay and jewellery applications. All pcs are A grade.