Nivada Grenchen Chronomaster Aviator Sea Diver 105-25249

This is an obscure reference from the final generation of automatic, Valjoux 7750-powered Chronomasters. While it belongs to the Ref. 105 family, the specific meaning of the secondary number 25249 is not well-documented or consistently associated with a specific visual style in the same way as the references for steel, PVD, or gold-plated cases. Such numbers were often used by manufacturers for internal cataloging, potentially designating a specific dial that was not produced in high volume, or a configuration for a specific market or retailer. Despite the ambiguity of the secondary number, the watch’s core specifications are certain: it uses the Valjoux 7750 movement and is housed in the 42mm cushion case. For collectors, this reference number represents one of the many minor, often hard-to-trace variations that occurred during the tumultuous but highly diverse watch production period of the late 1970s and early 1980s.