Biconcave eyepiece lens mounted in a cardboard ring. The edge is covered with red marbled paper. The lens diameter is c. 35 mm, the focal length ‑67 mm (the negative focal length means that the lens is diverging). The glass has a slight green tint and contains small bubbles. The lens is mounted in a cardboard housing covered with red marbled paper. The tube, 46 mm long and 55 mm in diameter, has a nineteenth-century label with the inscription "Eustachio Divini Roma 1665 acuto per braccia 4" i.e., diverging eyepiece for a telescope of 4 braccia (2,340 mm)