This Arnold & Son Perpetual Moon 1GLAS.U02A.C122S is an out-of-this-world horological experience. If you are into moon phase timepieces, this is the watch for you.

The Arnold & Son HM Perpetual Moon Phase is driven by the manufacturer’s A&S1512 caliber with 27 jewels and an impressive 90-hour power reserve. The movement itself is nickel-silver with rhodium treated Haute Horlogerie finishing such as manually chamfered bridges with polished edges, fine circular graining, Côtes de Genève rayonnantes, and blued screws.

A 27-jewel caliber delivers an extremely accurate moon phase timepiece—only one day’s deviation every 122 years (at which point a single push of the corrector syncs it up for another 122 years)!

The 29-mm moon phase disc runs from 10 to 2 o’clock and is one of the largest moons on the market. The moon itself measures 11.2mm. A second moon indication at the back of the movement (visible via a transparent sapphire case back) can be set using a graduated dial and a pointer hand that allows for a more exact setting.

The polished stainless steel case measures 42mm (excluding the crown), is 11.43mm in height, features a water resistance to 30 m / 3 atm, and rests upon a black alligator leather strap with a buckle.

Gaze through the cambered antireflective sapphire crystal to encounter the stunning translucent enamel with guilloché decoration dial that showcases a blue guilloché moon disc with a gorgeous silvered moon. The beautifully minimalistic hands and hour and minute markers add to the quiet beauty of the timepiece.

Standout features: Extraordinarily accurate and detailed moon phase function; beautiful translucent guilloché dial; impressive 90-hour power reserve.

Details at a glance:

• Model Reference: 1GLAS.U02A.C122S
• Case Material: Stainless steel
• Case Dimensions: 42 mm
• Case Height: 11.43 mm
• Movement: Manually-wound, 27 jewels, 90-hour power reserve
• Caliber: A&S1512
• Complication(s) / Feature(s): Standard time, perpetual moon phase
• Dial: Blue enamel guilloché and a blue guilloché moon disc with a silvered moon
• Crystal: Scratch-resistant sapphire
• Winding Crown: Push / Pull
• Water-resistance: 30 m / 3 atm
• Band: Black alligator strap
• Clasp: Stainless steel tang buckle
• Country of Origin: Switzerland
• Retail Value: $18,600
  
• Condition: Pre-owned in near mint condition; strap shows minor wear
• Comments: Includes manufacturer's box (inner pillow currently is not available, it's been ordered and will be provided at a later date); instructions manual, certificate of authenticity, and stylus for setting moon phases