The letters and numbers nearby (often in a format like H500 , E111 , or B612 ) identify the specific movement caliber inside. 2. How to Identify Your Exact Movement Caliber

Use a jeweler’s loupe. Look for a smaller, fainter engraving reading “Cal. XXXX” where XXXX is a digit-letter combo (e.g., Cal. 8651, Cal. E168). Citizen often places the caliber near the bottom edge of the case back.