The Isobrite chronograph T100 Swiss tritium lightweight polycarbonate watch is the first and only in the market. The Isobrite ISO401 watch features a Swiss Made Ronda 5040.D Quartz chronograph movement, an anti-reflective scratch resistant sapphire crystal, a tritium illuminated number 12:00, two tritium markers on the unidirectional bezel and 200m of water resistance and T100 bright tritium tubes. The watch band nitrile-butadiene rubber or NBR is the most durable band available and much more expensive. It is used in fuel hoses, gaskets, rollers which requires a heavy duty reliable application and resistance to oils. This provides one super tough comfortable band. 2 years warranty.