21st century, Glashütte, Germany
Langematik, "Sax-O-Mat" perpetual calendar, Ref: 310.025
Dial: matte silver dial with applied polished white gold Roman numeral hour markers, rectangular date aperture, sub-dials for day of the week with day/night 24-hour indicator, months with leap year, sub-seconds with moon-phase aperture
Movement: 43 jewel, Cal: L922.1, #36709, Sax-O-Mat with zero-reset feature, 3/4 plate in German silver finish, fausses côtes decoration, straight line lever escapement, monometallic balance adjusted to 5 positions, self-compansating balance spring, swan neck micrometric regulator, 21K gold and platinum bi-directional automatic winding rotor, engraved balance bridge, #36709, signed: A Lange & Söhne Glashütte SA
Case/Strap: circular polished and brushed platinum case with straight lugs, #146753, polished rounded sapphire glazed front bezel, screw-down with six screws, sapphire glazed rear back, push button at 10 o'clock for date function and flush profile push pins for adjustments, hallmarked, signed: A. Lange & Söhne Glashütte SA, skin strap with corresponding platinum Lange buckle, signed and hallmarked, with stock box
46mm x 39mm
116 grams gross

Very good overall condition. Winds, sets and runs. Dial: Very good conditon. Movement: Very good condition. Case: Very good condition. Very light surface wear. Wear to skin strap; buckle in good condition.