Trimix is a breathing gas used in deep-sea diving that consists of three components: oxygen, nitrogen, and helium. The combination helps reduce the risks associated with deep dives, such as nitrogen narcosis and oxygen toxicity. By replacing some of the nitrogen with helium, divers can safely explore greater depths. Divers typically use trimix for dives deeper than 30 meters (about 100 feet). The specific ratios of each gas can vary based on the dive's depth and duration. Proper training and planning are essential for using trimix effectively, ensuring divers can manage their gas mixtures and avoid potential hazards.