This is a stainless steel Glashutte Senator Moon Power Reserve 39-44-04-12-04. It has an alligator leather strap with a stainless steel folding deployment buckle, and a scratch resistant sapphire crystal. It has a pull out winding crown, a corrector at 11 o'clock on the left side case band, and an exhibition sapphire display case back engraved with "GLASHUTTE ORIGINAL – ST. STEEL – 5 ATM," and a serial number. The 39.9mm diameter solid round three-body case, straight lugs, and angled concave bezel, are all polished/brushed. The dial is silver with applied faceted steel baton hour indices, polished steel feuille hands, and there is a perimeter black minute/second scale. It has a center sweep second hand with a Glashutte logo counterbalance, and there is a date aperture window at 6 o'clock. The crescent-shaped moon phase is between 10 and 11 o'clock, and there is an up/down fan shaped power reserve register between 1 and 2 o'clock. It has a 40-hour power reserve at full wind, and it's water resistant to 50 meters/165 feet. The 11.7mm thick case, dial, and movement are all signed.
This Glashutte Senator Moon Power Reserve 39-44-04-12-04 has a mechanical automatic self-winding Glashutte caliber 39-44 movement. It's rhodium plated, with fausses cotes embellishment. It's constructed with 36 rubies, a shock absorber mechanism, a straight-line lever escapement, and a monometallic balance that's adjusted for temperature and 5 positions. It includes a self-compensating flat balance spring, a swan-neck regulator, a hacking seconds mechanism, and a rotor with a 21K gold segment. The movement oscillates at a frequency of 28,800 vph (4 Hz).