Ratio FreeDiver Helium-Safe 1000M Sapphire Automatic 1068HA96-34VA-RED Men's Watch Free divers and scuba divers alike understand the importance of a dive watch. Time your dive, oxygen or track elapsed time besides tracking local time real time. Its big clear dial markings are readily visible even under low light; thanks to its bright, glowing lume.The sapphire glass is a bonus; it is more resistant to scratches and chinks from sudden impacts.