Isobrite ISO503 Stainless Steel Master Diver Series Watch with NBR Band T100 illumination lasts up to 50 years, which is double the life of a standard T25 tritium watch Anti-Reflective Scratch-Resistant Sapphire Crystal Stainless Steel Case, Nitrile Butadiene Rubber (NBR) Band Unidirectional Bezel with Tritium Marker 10 Year Lithium Battery