Tetra Ochra / Open Case Back

The NOMOS Tetra Ochra 437 is part of the Tetra Origins series, a set of four square stainless steel watches with distinct color compositions and the hand-wound DUW 4001 calibre. This version uses an ocher yellow dial with rhodium-plated hands and a contrasting small seconds display, placing the Tetra’s angular case architecture within a warmer, pigment-like color scheme. The stainless steel case measures 29.5mm by 29.5mm, with a height of 6.5mm and a lug-to-lug length of 40.5mm. It is fixed with four screws and fitted with a sapphire crystal front and sapphire crystal case back. The double lugs are one of the defining external details of the Tetra design, while the slim case height keeps the square format relatively flat on the wrist. Water resistance is rated to 5 atm. The ocher yellow dial uses the Tetra’s mixed numeral and marker layout, with a square minute track and a small seconds display at 6 o’clock. The seconds sub-dial combines red and two shades of yellow, while the seconds hand itself is yellow. Rhodium-plated hour and minute hands contrast with the warm dial surface and allow the watch to be visually separated from the gold-handed Tetra variants. Power comes from the NOMOS DUW 4001, a manually wound in-house calibre measuring 10 ½ lignes in diameter and 2.6mm in height. It has 17 jewels, a power reserve of up to 53 hours, and uses the NOMOS swing system. The movement is visible through the sapphire crystal case back. The watch is supplied on a beige vegan velour remborde strap with an 18mm lug width.