Orion 33 Duo / Open Case Back

Reference 320 is the sapphire-back version of the NOMOS Orion 33 Duo, a compact two-hand Orion with a 32.8mm stainless steel case, white silver-plated dial, and gold-coloured hands. It omits the small seconds display used on standard Orion models, giving this reference a reduced hours-and-minutes layout. The case measures 32.8mm in diameter, 8.5mm in height, and 42.3mm from lug to lug. It has a domed sapphire crystal front and a sapphire crystal case back, distinguishing it from the closed-back version of the Orion 33 Duo. The Orion case is defined by its rounded, lenticular profile, curved crystal, and tapered lugs. Current specifications list water resistance at 5 atm, an increase from the earlier 3 atm rating. The galvanized white silver-plated dial is free of numerals and subsidiary displays. Fine hour markers structure the dial, while the gold-coloured hands provide the only time indication. Some NOMOS descriptions also refer to mocha-brown typography for this version, though the current specification lists the dial more generally as galvanized and white silver-plated. Power currently comes from the NOMOS DUW 4001 Duo, a manually wound in-house calibre based on the DUW 4001 and adapted for smaller two-hand models. It measures 10 ½ lignes in diameter and 2.6mm in height, with 17 jewels and a power reserve of up to 53 hours. Earlier examples of this reference were fitted with the Alpha.2 movement. The watch is supplied on a beige vegan velour remborde strap with a 17mm lug width.