Shakudo menuki signed "Sadanaka" with Kao. Sadanaka was a student of Ichinomiya Nagatsune, he was active in the second half of 18th century. Based on example I have, signature looks genuine.
Made of shakudo with eyes inlaid with gold.
Made in Edo Period.
1: 38 mm x 12 mm
2: 38 mm x 11 mm