Momentum by St Moritz watch corp M1 Deep 6 Dive Watch Superluminous means that you charge the indexes in the sunlight and they glow in the dark (when the absorbed sunlight is released).Further technical information : http://kronometric.org/article/lume/ Quartz movement Date feature, super luminous hands and indexes, unidirectional rotating bezel Black polyurethane strap with stainless steel buckle closure Water resistant up to 660 feet (200m) Water resistant to 660 feet (200 M): suitable for recreational scuba diving