Continuing in the footsteps of her larger sister the Nautilus reference 3700, the Aquanaut launched in 1997 was the new sports line introduced by the firm. This first generation of the Aquanaut can be recognised by the tritium lume used that turns to a warm yellow color such as this example, its nontransparent screw-down caseback as well as its double deployant clasp stamped Nautilus. Only produced in 1000 pieces, these have already found their homes in most collectors of sport steel Patek Philippe’s.