For the professional or the recreational diver, the ability to read his or her instruments is not just a desirable option or wished for convenience, it's a must! The P6504 meets this challenge. It is the only divers watch to be equipped with mb-microtecs gaseous tritium light sources (GTLS) in a blue colour. Under water, due to refraction the colour blue is the only (last) colour still visible beyond a certain depth, thus the P6504 guarantees the diver access to vital information at a depth where other watches fail to perform. Available with either yellow or orange dial and easy to clean rubber strap.