Nivada Grenchen Chronomaster Aviator Sea Diver 85004 / 4076

This reference demonstrates Nivada’s strategy of market segmentation during the late 1960s and early 1970s. Externally, the Ref. 85004 / 4076 is identical to the 85004 / 3730, sharing the same 38mm straight-lug case, hands, dial design, and versatile bezel. The critical difference, denoted by the secondary reference number 4076, is the use of the Valjoux 7733 caliber. The Valjoux 7733 is a robust and highly reliable cam-lever (or coulisse) operated manual-wind chronograph movement. It was developed as a more cost-effective alternative to the column-wheel Valjoux 23, allowing Nivada to offer the Chronomaster at a more accessible price point. The movement was a workhorse of the Swiss watch industry in the 1970s, known for its durability and ease of service. By offering two versions of the Ref. 85004 with different movements, Nivada catered to both buyers seeking the prestige of a column-wheel chronograph and those who prioritized proven reliability and value. The existence of this reference is a perfect illustration of the practical business decisions made by watch manufacturers during the height of the mechanical chronograph’s popularity.