This is a pocket watch by AERO. The size is about 23mm. It's a manual wind watch and its operation has been confirmed, but the daily rate has not been checked. A necklace is included for use as a pendant. It is a used item in good condition. I believe the material is silver, but I haven't confirmed it as the back cover cannot be opened. Please ask any questions in the question box. No returns or cancellations accepted.