The Bear Grylls Survival Series model has a CARBONOX  case. CARBONOX  is an exclusive Luminox material based on carbon that is light, hypoallergenic, extremely durable and resistant. Made for Diving The bezel has a special diving zone counting up marking 1-20, set off by a different color (blue or orange) for easy reading. This feature is crucial in diving situations because it measures the timing of mandatory decompression stops as divers slowly resurface from deeper dives. The uni-directional turning bezel serves the purpose of avoiding a situation where a diver may accidentally knock the position off while measuring the amount of oxygen he/she may have left. Since the bezel only turns counterclockwise, this ensures that, even if the bezel is moved, you would still be safe. Never Give Up The dial of XB.3729.NGU is stamped with Bear Gryll's favorite mantra - to remind you that, if it's a goal worth achieving, hang on in there and NEVER GIVE UP! Never Give Up is a vital attitude for survival in any conditions. According to Bear Grylls, whether you make it out alive will largely come down to you  your attitude and your actions. Luminox Light Technology The unique Luminox Light Technology (LLT) ensures at-a-glance visibility - in fact, the technology provides a constant glow 24/7, no matter what the conditions are, for up to 25 years. The self-powered illumination system utilizes tiny micro tritium gas tubes to create ultimate visibility in complete darkness. Features: Origin: Swiss Made Always Visible: Constant glow for up to 25 years Function: Time Date Bezel: Uni-directional rotating Case back: 316L Stainless steel screw in Crown: Screw in, double security gasket, crown protected