Wittnauer Skin Diver

c. 1963-1969, during the golden era of recreational-diving "skin diver" tool watches, under Longines ownership.

2 references

Reference	Variant	Years	Dial	Size
4000	Skin Diver, black dial	1963–1969	black	38 mm
4000-SIL	Skin Diver, rare silver/cream dial	1963–1969	silver	38 mm