The manufacturers of all the general purpose SCUBA regulators we stock describe them as suitable for use in warm, temperate and cold water conditions. Based on testing standards we define those water temperature ranges as follows:

• • Warm water is greater than {68°F | 20°C} to a maximum of {90°F | 32°C}.
• • Temperate water is between {68° to 50° F | 20° to 10° C}.
• • Cold water is less than {50°F | 10°C} to a minimum of {40°F | 4°C}.
• • Freezing water conditions below {40°F | 4°C} incurs significant additional risk that requires specialized training and specialized equipment.

Among the regulators we stock, only the Xstream series is described by Poseidon as suitable for diving under ice in freezing seawater conditions down to {29°F | -2°C}. However, the XTX series is a close second, described by Apeks as suitable for use down to {36°F | 2°C} and a popular choice among "ice divers".