Plastic Ferrules CodeNameThreadLength 52OPT06 Optifix 06 M6 23 mm 52OPT08 Optifix 08 M8 30 mm 52OPT10 Optifix 10 M10 37 mm 52OPT12 Optifix 12 M12 44 mm 52OPT16 Optifix 16 M16 58 mm