This is a double signed Erster-Squale Dive Watch. It is in nice vintage condition, with some light corrosion on the dial around edges. The original two-color hands are in excellent condition, and really make this example stand out. The case is very sharp and unpolished. The original case back is signed and in great shape.
For more information on Squale, and their history, see this fantastic article on the brand by Hodinkee: