Whether you're deep in the sea on a diving vacation or just off shore honing your freediving skills, the Suunto D4 wristop computer has a multitude of useful functions that will keep you informed every meter of the way.

• 4 operating modes (Air, Nitrox, Free, and Time. See below)
• Complete decompression stop data
• 80h profile and logbook memory
• Lifetime history and memory (scuba and freedive)
• Daily history (freedive)
• Profile memory bookmark
• USB compatible PC-interface
• Multi-step ascent rate indicator
• Personal adjustment
• Altitude adjustment 0-3000m (0-10000ft)
• Automatic safety stop countdown
• Electroluminescent illumination (back light)
• Depth display range 0-100m (0-328ft)
• Audible alarms
• Maximum depth alarm
• User-selectable metric or imperial units
• Battery power indicator and warning
• Calendar clock
• Dual time
• Stopwatch
• Daily alarm
• Display shield
• Suunto Deep Stop RGBM

Free Diving Mode:
• Depth sampled three times a second
• Deepest sample recoded every second
• Surface time in seconds
• Most recent dive's time and max depth
• Day's deepest dive and its length
• Day's longest dive and its depth
• Notified surface alarm
• Notified depth alarm

Air Mode:
• Audible and visual alarms for dive time and depth
• Current depth and max depth
• Current time, dive time, and decompression time
• Temperature

Nitrox Mode:
• Oxygen content adjustable from 21% to 50%
• PO2 limit adjustable from 0.5 to 1.6 bar

Deep Stops:
• Stop time countdown in seconds
• Safety stop / deep stop options
• Adjustable deep stop time

Logbook:
• Up to 240-hour profile and logbook memory
• Lifetime history memory
• Daily history (Freedive Mode)
• Profile memory bookmark